Theory:Doctor Who television discontinuity and plot holes/Journey's End


 * When Jack shoots the Supreme Dalek to no avail, you can clearly hear the sound of his revolver's bullets ricocheting of its casing.
 * How is one person with time lord intelligence able to destroy the daleks when they are at full power yet the entire time lord race are unable to over several years.
 * Because Donna was in the same room as the device which had absolute control over the Daleks.
 * Also all these Daleks are made using Davros DNA which the Daleks in the time war weren't so they would be able to build a machine connected to every Dalek in existence
 * Also she was not expected to be a threat.


 * Donna claims she is able to use her time lord intelligence better because she is a human, but it is the Doctor[a time lord] who has been defeating the daleks for years easily he eradicated their home planet stopped their invasion of earth why is the Doctor so utterly useless in the face of Davros, so easily overpowered terrified unable to beat him without the aid of his assistant bit different to the seventh doctor's "every time our paths have crossed I have defeated you"
 * While it is true that Donna's claim can be considered a little biased and/or suspect, it is also true that the Doctor rarely defeats anyone (Davros, Dalek, or otherwise) without any help. That's one of the reasons he has cited at times as to why he continues to have companions. In this instance, Donna would not be there nor would she have the necessary intelligence without the Doctor's influence. Once again, it is a joint effort between the Doctor and others (many others, in this case) who defeat Davros and the Daleks.


 * Also, when it comes down to it, it's not so much that Donna uses her intelligence better, as that she (and likewise the Meta-Crisis Doctor) uses it more ruthlessly than the Doctor ever would. If the Doctor couldn't stop the Daleks without genociding them, he'd at least hesitate (as we've seen time and again), but Donna (and MC10) don't.
 * Its also worth noting that the Doctor is half human.


 * that was retconned early on in nuwho
 * The Doctor is half human!


 * When the spotlight then comes on onto Caan, Rose questions what the creature is. Having seen the true Dalek form before (TV: Dalek), shouldn't she know what it is?
 * It's not just the Kaled mutant she's asking about, it's also the destroyed Dalek casing, the fact that it is chained up, and that it's cackling maniacally under a spotlight.


 * If the Doctor under went a regeneration (stopping it short if changing his appearance), then surely he would still under go regeneration trauma of some sort.
 * The Doctor states that the process first repairs him then changes him.
 * If that's so, then why would regeneration require him to alter his appearance at all? If it starts out by just repairing the original body to (apparently) perfect health, why bother to change it afterwards?
 * Because that is the process of regeneration. Regeneration is a natural thing and was not created, so the processes cannot be altered.


 * Also, possibly because there would be no point in keeping an older or more frail body, than changing to a new one.


 * Also, not all regenerations cause regeneration trauma.


 * It is unclear how regeneration entirely works. It depends on the manner of death. Regenerations are probably meant to occur 'naturally', when a Time Lord's body is failing. It makes sense for them to 'rejuvenate' themselves as well.


 * By destroying every Dalek including the ones on Earth the Doctor would have killed the Dalek that featured in the episode Dalek thus making the events of said episode completely non-existent.
 * That Dalek's dalekanium wasn't receiving power from the Crucible. The Doctor Clone destroyed the Daleks by maximizing the power feeds and blasting them back. (In other words, he only destroyed the Daleks that had been created after Dalek Caan rescued Davros from the Time War.)


 * Also, even if he unwrote the events of that episode, so what? History can and does change. It still happened in his past (and in Rose's). And we haven't seen anyone else since 2009 who would know whether or not they happened.


 * If the Reality Bomb destroys every reality, surely the Doctor would have had to prevent alternate reality versions of Davros from detonating reality bombs, lest they destroy this reality as well?
 * As there is only one version of the Doctor across all realities the Time War only happened in 'our reality', so only one version of Davros as part of Time War exist.
 * It hasn't been stated there aren't any parallel versions of the Doctor.
 * Actually, we've seen alternate-timeline versions of the Doctor in non-TV stories, and Battlefield hints at one as well.


 * Also if there was no doctor in an alternate reality then surely the Daleks would advance greater than these one as there would be no doctor stopping their plans.
 * Only if there was a Davros in that reality; the statement you're replying to specifically says that neither the Doctor nor Davros exist in those other realities.


 * The Doctor says a New reality is created by every decision we make. So I personally think this Anti-Monitor based weapon would only destroy the 'Nearest' universes, as in closest to them.
 * That's not strictly impossible, but there's no evidence for it, and it's clearly different from what's said in the episode.


 * It's something of a matter of perspective. Given that we don't (and can't) fully understand howe the weapon functioned, we can't say for sure if Davros was right in his assumption or if it could have ben otherwise stopped.


 * Regardless, if we accept that there was only one "Davros rescued form the Time War", then only one Reality Bomb would have been created.
 * I think this is the key. Whether there's only one Doctor, one Davros, and one Time War, or an infinite number of them, what Caan did was so incredibly impossible that it only happened once. Therefore, there's only one post-War Davros with one Reality Bomb in all of the realities.


 * Maybe it was a fixed point in all realities and universes that the doctor stop Davros from detonating the Reality Bomb?


 * Fixed Points in all realities? Perhaps you should interpret the Reality Bomb your own way. However I personally think it is likely Davros would exaggerate. In their arrogance the Daleks wouldn't consider realities they couldn't find. It is unknown how the Multiverse works, there are theories of Level I and Level II Multiverses. It is probably best to leave the Reality Bomb unclear.


 * Remember,a paralel universe is created from our decision.Two options.One universe for each.Caan had to choose whenever to save him or not.In our universe,he choosed to do it,and in the other one,he didn't.Therefore,there is only one universe in which Caan saved Davros..


 * Actually, if there were parallel universes created from every decision, then universes would still be created after Caan saved Davros. For example, if the Dalek in the street had aimed at a different angle, the Doctor could have been killed outright, preventing the Meta-crisis, which could have resulted in the Reality Bomb detonating successfully. Of course, maybe in every universe Davros is defeated or even a universe where the detonation succeeds is somehow contained.


 * If Dalek Caan wanted destruction to come to his race, why didn't he just kill himself rather than doing an emergency temporal shift, rescuing Davros, and allowing Davros to create an entirely new race of Daleks to be destroyed?
 * It was his emergency shift that helped him see what the Daleks were - but by that time, he had already saved Davros, so it was too late to stop him.


 * Some of the scenes used in the flashbacks of people that have died for/because of the Doctor are scenes that the Doctor hasn't witnessed, for example, Harriet Jones's extermination that the Doctor hadn't found out until Davros mentioned it, also in the scene where the Hostess sacrificed herself, the Doctor was in a possessed state.
 * The Doctor is aware of these individuals dying, so he has a retrospective moment in response to Davros' statements. The scenes shown are for our benefit, and not necessarily the only ones that the Doctor was "picturing" in his mind.


 * Wouldn't destroying reality change Dalek history, e.g Dalek invasion of Earth.
 * The Daleks' ultimate goal is to become the supreme creatures in the Universe. Destroying reality would do this, so the existence of any past invasions would be irrelevant to them.


 * If any mention of the Doctor or the TARDIS would cause the Time Lord consciousness within Donna to reawaken and burn up her mind, isn't the Doctor taking a tremendous risk by letting Donna see him in the Nobles' house?
 * The Doctor said tell, so seeing him won't kill her unless someone tells her who he is. Additionally, it's better for him to gently test this while he's still there and could potentially fix any problem that did occur, rather than hope he was right and potentially let her find out when he's not around.


 * Why didn't Davros activate a holding cell on Donna when he did with everyone else?
 * Davros didn't place a holding cell on Martha, Mickey, Jackie, Sarah or Jack, either. Donna had been zapped and knocked unconscious, so it would have been very unexpected for him to put a holding cell on her.
 * Also he probably didn't think Donna would be able to understand the controls.


 * The DoctorDonna immobilises all the Daleks but yet the Supreme Dalek descends to the vault and destroys the Magnetron. Also they stopped all access to the vault so the Supreme Dalek wouldn't have had access there anyway
 * The Supreme Dalek is twitching as it descends. It probably had a personal backup power source. And being the Supreme Dalek, it presumably had unlimited access to anywhere onboard that it wanted to go.


 * Doctor Donna incapacitates the Daleks by manipulating keys. Why are there keys that could only be manipulated by hands on a Dalek vessel?
 * Davros has humanoid hands he could have used to keys. Some Daleks have claws instead of plungers.


 * When the Earth was returned to its rightful position, the moon is seen to be still in its place (it did not travel with the Earth as we must assume the satellites and the rift did) and presumably resumed orbit. Wouldn't it have floated off toward the sun or another planet without the Earth's gravity to keep it in place?
 * The Earth and the Moon actually revolve around the Sun as a unit as they also revolve around each other (as the Earth in much more massive, the center of revolution for the Earth-Moon system is actually beneath the Earth's crust). If the Earth suddenly disappeared, the Moon would continue to travel around the Sun in the Earth's orbit. Granted, recapturing the Moon and putting the Earth-Moon system back together would be an interesting exercise in celestial mechanics, but two Doctors and a Doctor-Donna are certainly up to the challenge.


 * The Doctor acknowledges that the Earth is in for a period of unusual weather patterns, likely caused by the Moon reinstating itself.


 * To get Earth home that quickly they would have been going at the speed of light and as the Doctor explained in The Stones of Blood traveling past the speed of light causes the traveler to arrive at their destination before they left, meaning they could have arrived not to soon after Earth left its original place.
 * Given the distances involved, it seems unlikely the TARDIS "towed" the Earth through normal space-time. Plus the earth had been missing for quite a long time, so maybe it arrived just after the Tardis dematerialised to head for the Shadow Proclamation.


 * When the Doctor remembers those who have died because of him, he recalls characters from the Ninth Doctor era, so shouldn't he also remember individuals such as Adric, Katarina and Sara Kingdom, too?
 * Normal tendency would be to remember the most recent ones first. Whether they cross his mind at all or not in those few seconds is of course unknown.


 * From a storytelling perspective, it makes more sense to include flashbacks to recent guest stars.


 * We're not a literal picture of something on a screen in the Doctor's brain. (Nobody literally remembers things as a stream of 2-dimensional images, after all.) What the producers and director chose to show us was the best representation, for the audience, of the idea of the Doctor recalling those who had died for him. Because most of the audience would have no idea who Katarina is, and the black-and-white footage available for her would have been pretty jarring, they didn't use it.


 * When the Doctor Donna seals the vault how is the Supreme Dalek supposed to descend upon it?
 * The Supreme Dalek has the authority or codes to override the seals.


 * The Dalek sealed in the time bubble at Torchwood should not have been destroyed when the other Daleks were. It would have been insulated from all events occurring in time.
 * It is unknown how a time lock functions.


 * If the Medusa Cascade has been taken a second out of synchronization with the rest of the universe (as stated in The Stolen Earth), then how is the Reality Bomb detonation supposed to affect anything outside the Medusa Cascade?
 * The signal that was sent to the Doctor by Torchwood managed to reach the normal universe, so the reality bomb can as well.


 * How can the TARDIS tow the Earth back home if the Medusa Cascade has been taken a second out of synchronization with the rest of the universe?
 * Given the distances involved, it seems unlikely the TARDIS "towed" the Earth through normal space-time.


 * Why was Davros not shocked to see that Jack was alive after being exterminated?
 * He was not present for the actual extermination, hence didn't necessarily know he had been shot.


 * Wouldn't Donna see something on the news about the Earth moving and burn up?
 * As the Doctor said, she'll think it of a "Donna Noble story where she missed it all again". By the end of the episode, she was already discounting her friend's account of the story on the mobile phone.


 * Why hasn't Caan been given a new "casing" after being damaged in the Time War?
 * The disdain that the Daleks show for him is apparent, calling him "The Abomination". It is likely they did not consider him a Dalek.


 * If the Reality Bomb could destroy all universes then wouldn't a reality bomb from a different universe then destroy the Daleks?
 * The reality bomb does not target Daleks otherwise their bomb would destroy them.
 * No, Davros explains that the Daleks are safe because of the Crucible.


 * Clearly, the Reality Bomb would destroy any Daleks in other universes (unless they were busy detonating their own Reality Bomb in their own Crucible at the same time), but so what? Davros wants his Daleks to be the supreme masters of creation, not some other Daleks that may have been created by some parallel-universe Davros (or, worse, by someone else).


 * There is no reality bomb from a different universe. As explained elsewhere, whether or not there's one Doctor, one Davros, one Time War or many of them, what Caan did is so incredibly impossible that it only happened in one universe.


 * Gwen and Ianto use their guns against the Daleks knowing that bullets won't harm them. However, Torchwood does have more advanced weapons, as seen in Something Borrowed.
 * Gwen may not know where some of the more powerful weapons are or have the strength to lift them.


 * In Doomsday, when someone used a dimension jump device, they stayed in the same location as they were before they jumped. So, surely, when Mickey and Jackie travelled from their parallel universe, they should have been teleported to the Earth's original location, and ended up jumping to where the Earth used to be? Also, what a coincidence that they landed just where Sarah Jane was about to be exterminated?
 * It's very possible they've had time to perfect the technology. Also, Rose was on the planet. For all we know they were tracking her location and altered their transit system / reality jumping devices to compensate for the move of the planets.
 * Location in Space is relative. The two Earths are linked together, even if the one is moved. They may have a way of viewing their destination in the other universe before jumping, and thus deliberately jumped to save Sarah Jane. It would also explain Pete's handy rescue of Rose in TV: Doomsday.


 * If the Doctor has a device that can rewrite biology why does he not simply remove Donna's Time Lord DNA but order the TARDIS not to remove Donna's memories of her real self as it did in Human Nature (TV story)?
 * The Arch is used for Gallifreyan biology not Human biology.


 * We don't know that the Arch couldn't do such a thing, but we also don't know that it could—and presumably the Doctor knows more about it than we do. There's obviously some reason it wouldn't work; if we don't necessarily know what it is, so what?


 * When the Doctor and all his companions are inside the TARDIS at one point Martha looks directly at one of the cameras.
 * From her point of view she is looking at the Doctor.


 * When a Dalek says "exterminate!" when about to kill Donna, its dome lights do not light up.
 * When multiple Daleks are on screen, the lights blinking allows the audience to know which one is speaking; it would be a bit of discontinuity not to have them blink even if the Dalek is alone. Traditionally the lights flash on the syllables, so the lights should have blinked 4 times for "exterminate".
 * It is possible that the dalek you see doesn't actually say the word "Exterminate!". As there is more than one Dalek it is likely that one of the Daleks you don't see actually says the word "Exterminate!".


 * Towing the Earth at light speed would cause a lot more than shaking on Earth.
 * As mentioned above, it's not literally "towing". Given the distances involved, it seems unlikely the TARDIS "towed" the Earth through normal space-time.
 * I don't know where everyone gets the "light speed" idea. For one thing, towing the Earth at light speed is actually more impossible than towing it faster than light. Plus, given the distance towing it at light speed would take many years from the outside perspective, while it would take no time at all from the Earth's perspective, neither of which is anything close to what we saw. But even if it were at light speed, why would that cause "more than shaking"? At light speed, an object has infinite mass (unless it has zero mass, like a photon), meaning any impacts with anything with finite momentum (interstellar hydrogen, whatever) have absolutely no effect.


 * The Supreme Dalek shows the Doctor, Rose and Jack a screen of the TARDIS in the core, surely they would have seen the TARDIS dematerialise.
 * They saw the TARDIS sink into the core, and it dematerialises at the moment they were expecting it to disappear due to its destruction.


 * Why didn't the Doctor remember Bliss if he remembered the rest of the Abzorbaloff's victims?
 * Bliss was placed on the Abzorbaloff's behind, so the chance of seeing her was slim.
 * It's also worth mentioning that Peter Kay played the Abzorbaloff, hence anyone on his behind would not be seen due to his obesity.


 * Why does The Doctor remember Ursula when she was saved by The Doctor in Love and Monsters from absorbing into the path. It was clear she survived and hadn't died so The Doctor never needed to remember her?
 * Even though she didn't die, the Doctor would still feel guilty because of his intervention in her life caused her to nearly die.


 * Sarah Jane Smith claims her son Luke is 14 when he was grown as an adolescent about a year ago.
 * Luke is consistently referred to as his equivalent biological age throughout TV, however, presumably for convenience rather than retelling his entire creation story every time.


 * Even forgetting the out-of-universe storytelling perspective, imagine yourself in-universe as Sarah Jane. How many times would you say, "Luke was only born a year ago, but he was physically 13 years old at the time" before you got sick of it and started saying "Luke is 14"?


 * If this (very public) event happened in 2009, why does Henry van Statten not recognise the Dalek in 2012?
 * There is a good chance that Henry van Statten had seen the Daleks during their invasion. But considering that the Daleks decided to simply declare extermination then proceed to perform the invasion rather than actually publically announce themselves in detail. As a result, it is unlikely that members of the general public were even aware of the Dalek's motives and who they actually were.


 * Or maybe he and his team was in his underground base at the time and not seen the event.


 * It is unlikely he would have missed it, the whole earth moved and van statten investigates something even if it is just a light in the sky.


 * Also the public are aware of the daleks as evidenced by adeliade and others who mention them, if he didn't know about them and he's supposed to investigate aliens he would have to be pretty stupid.


 * The Doctor states in Flesh and Stone that the event was erased from history by the cracks in time, so nobody except the Doctor should remember it at this point, therefore Henry van Statten wouldn't remember or recognise the Dalek.
 * This also explains why other characters from later in time didn't remember the Daleks, from Zoe to the people who faced the "first" invasion (in the timeline of the series, not chronologically).
 * Or maybe not; see the next answer.


 * Also, wibbly-wobbly timey-wimey. The Doctor first visited a 2012 where there hadn't been a Dalek invasion. But, because the Daleks have time travel, they were able to change history, so the Doctor later visited a 2009 where there _was_ a Dalek invasion. This new 2009 isn't in the past of the original 2012; it's only in the past of the new 2012. Meanwhile, the cracks/reboot mean that there's now a third 2012 where the invasion never happened again. So, it's probably that the backstory of Dalek would have gone very differently if the Doctor had visited 2012 after the invasion (in his timeline), but it might not be much different if he visited it after the reboot (in his timeline).


 * To put it into two brief quotes: "time is not linear", and "history can change".


 * Before Donna loses her memory, there are flashbacks of her adventures which are seemingly parts of her memory. But one of the flashbacks is from the parallel world created around Donna, which she had trouble remembering when the timeline was mended.
 * It's entirely possible, that during the process in which her memories were erased, the Doctor purposefully brought some fleeting fragments of Donna's time in the alternate reality to the forefront for him to erase.


 * Why do none of the Daleks in this episode or the previous one possess force fields?
 * Since Gwen and Ianto's bullets do not effect them, it is likely that they did have forcefields, but there weren't any of the usual slow motion shots that showed them.


 * Why do the Daleks need the entire human race alive for one experiment? Couldn't they have just got a small and unintelligent animal, and test it on that before the plan goes into action?.
 * It is only one experiment, and the Humans are an enemy of the Daleks, and an ally, and favourite race of the Doctor, so it is not that extreme that Daleks would test it on the Humans, and why would they test on animals when they have Humans to terrorise.
 * Because the Doctor says the Daleks fear him (TV: The Parting of the Ways) and wouldn't risk him catching up to them.


 * Also, the Daleks are 'slaves' to logic (TV: Destiny of the Daleks) and wouldn't risk keeping a planet alive that are full of 'pests' that they know have caused interference with their plans.


 * Also the planet itself may have been integral to their plans and why not start with the humans as they have most likely been the most recent planet taken.


 * If the TARDIS translates everything for anyone who's been in it, why didn't it translate for Martha when she first arrived in Germany?
 * Because the Tardis was not on earth at the time, and Martha could speak German.


 * Why does the Doctor have to remove Donna's memory after the Human-Time Lord Meta-Crisis and not the Meta-Crisis Tenth Doctor's? When the Doctor says there has never been a Human-Time Lord Meta-Crisis before now saying that Donna knows why, which she responds "because there can't be", he proceeds to wipe her memory of him. If "there cant be" why can the Time lord-Human survive yet the Human-Time Lord can not?
 * The reason why the Human-Time Lord cannot survive is because her human brain can't handle the expanded consciousness of a Time Lord. A Time Lord, however, could easily handle a human consciousness without ill effects.


 * If the Children of Time refer to the companions in this episode, can old companions such as Jo Grant, Peri Brown and Ace be considered as being members of the Children of Time?
 * It's just a poetic term being used by Caan and Davros. It doesn't have a specifically designated membership.


 * The point of regeneration is that is changes your body because it is dying not that it heals the one you already have, but the Doctor implies changing bodies is just a side-effect of regeneration.
 * The exact steps that a regenerating body goes through have always been left vague. Each regeneration adds a little more to the mystery surrounding it.


 * What the Doctor says is pretty clear: first it heals him, then it changes him. The two are normally inseparable, but this isn't a normal case.


 * Davros stated in the previous episode that he created all the Daleks on the crucible after being rescued by Caan. If so, why did he not condition them to be subservient to him, like he did with the Imperial Daleks, rather then suffer their mistrust, and basically be enslaved by them?
 * Daleks are self-deterministic, and Davros wants them to be so that they can indeed become the supreme form of life in the Universe.


 * The multiverse is infinite, so couldn't it have universes without matter? And even if there aren't, can't the multiverse grow back?
 * Assuming Davros & the Daleks know this, he likely accounted for it. All realities of all types will be affected.


 * Universes without matter don't have anything to challenge the Daleks' superiority. And if universes with matter do grow back, the Daleks will be there from the start, and can establish their dominance long before anyone arises to challenge them.


 * During the doctors aborted regeneration, when he poured the extra energy into his cut off hand, his head temporarily disappeared. why did this happen?
 * It didn't. It was obscured by the energy pouring out of him.


 * In the deleted scene, the Doctor says that Pete's World is need of defending, giving his Meta-Crisis Clone a chunk of TARDIS so that he can "grow" his own TARDIS. However, it is established before that the TARDIS draws its energy from the universe it was created in, hence it would be futile in the first place to "grow" a TARDIS from the TARDIS coral because it belongs to The Doctor's universe.
 * The "TARDIS" hasn't been created yet. It's just coral, so when it grows, it will be able to draw power from the "diesel" of Pete's Universe.
 * Perhaps more importantly, the scene was not televised. So far as we know, it didn't happen.
 * It seems likely that the only reason there was a problem was that the Doctor wasn't prepared to end up in another universe. He's already reconfigured his TARDIS from powering over a link to Gallifrey to storing up power from time rifts (or it did so itself), and presumably he could accomplish a similar feat over the years it takes to grow a TARDIS from scratch. He just couldn't do so over the milliseconds it took to realize he was entering the wrong universe.


 * When the TARDIS lands in the park after towing earth back, people are walking around and acting like it's a normal day. they would most likely still be panicking about the invasion, or celebrating about the earth's return.
 * They are most likely used to things like this eg. Doomsday, The Christmas Invasion.


 * In TV: Turn Left, Rose mentions that Ianto and Gwen died destroying the Sontaran Mothership and that Jack had been transported to Sontar. Presumably, therefore, Rose had somehow learnt, when she was jumping between parallel worlds, that Jack had been rendered immortal (by her, but she may or may not know this). However, when Jack is exterminated by the Supreme Dalek, she reacts with shock and mourns him - only to be suprised when he appears on the intercom alive and well. Shouldn't she know that Jack would revive?
 * She doesn't know that Jack is immortal. She only knows that he has been transported to Sontar.
 * That's not the point. in "Born Again" (A short that happens between Parting of the Ways and The Christmas Invasion) Rose says "Let's go back and get Captain Jack" so she was aware he had been resurrected. So why is it a shocker that he's still alive to her? Especially considering she works with UNIT in Donna's World, and works for Torchwood in Pete's World.
 * The point is that she could simply not know that he'd ever died at all. She wasn't present when he died, and she brought him back to life as Bad Wolf, she didn't remember it. Which explains her words in Born Again - she didn't know Jack was killed and resurrected. And then later, without knowing about his immortality, she saw him being exterminated, and then she saw him alive - of course she's suprised, what's the discontinuity?


 * When placing the Osterhagen Missiles then they would disturb the gunk which turned people working on the Inferno Project into Primords and would have eventually destroyed the earth. (Following TV: Inferno)
 * Not necessarily. We don't know how deep they drilled, and we don't know if Stahlman's ooze is everywhere under the Earth or only in certain places.


 * As the Doctor said there are an infinite number of parallel worlds with different choices and outcomes, then there would have to be at least one where Davros succeeds in detonating the Reality Bomb, destroying reality.
 * That only happened in the one reality.
 * This is discussed above, multiple times.


 * As they are using the TARDIS to fly earth I noticed the scene with sarah-jane pushing a hand break is repeated, first in an overview of the entire team then again with a close-up she is doing this twice and whether she is supposed to it twice or not i always point this out to myself as a mistake
 * How is pressing the brake twice a plot hole or discontinuity?


 * Why does the Doctor say the duplicate doctor is so dangerous? He committed Genocide to the Daleks many times.
 * No, he refrained from committing genocide multiple times. He at some point caused the destruction of the Daleks and Time Lords once during the Time War, but the circumstances of that are unknown.


 * Davros says the Reality Bomb works by disrupting the electromagnetic fields holding matter together, but there are 3 other forces that do the same, gravity and the strong and weak nuclear forces. If the Reality Bomb doesn't stop these too then it couldn't work.
 * Exactly how it works is unknown, but the four fundamental forces each behave differently. Removing one from the universe, if that is indeed what the Reality Bomb was going to do, would indeed have catastrophic results. From a different perspective, most physicists believe that the four forces are actually different manifestations of the same force. If it is that fundamental force which Davros had found a way to disrupt/remove, then it could indeed produce an effect as was described.


 * Actually, most of the details are pretty well known. The electromagnetic force is what keeps electrons orbiting nuclei, so without it, there would be no atoms; the electrons would just go flying off into space. The electromagnetic force is also behind chemical bonds, and it's what makes solid things impenetrable. If you turned it off, matter would indeed fall apart--there would be a bunch of bare nuclei and free elctrons zipping around, with nothing to hold them together. And the other forces couldn't compensate. Gravity is too weak (well, you could keep some atoms the size of the observable universe, but that's not too useful), the strong force is range-limited and doesn't affect electrons, and the weak force... well, it's hard to explain, but it can't be used to hold atoms together. (And, even if dark energy turns out to be a fifth force, it's only repulsive, so it can't help either.) It's possible that, with the electromagnetic force shut down, the universe would undergo a phase transition into some new set of forces that would again allow atoms, molecules, solids, etc., but that would be just as catastrophic; at best, life could start up again after a few billion years.


 * So, the science here was perfectly sound--except of course for the 'how could you shut off the electromagnetic field all throught the universe?" question, which only gets the usual meaningless technobabble.


 * Of course the episode didn't explain that, but that doesn't mean it's impossible. Buckaroo Banzai used a very closely related idea (canceling the electromagnetic force was what made the mountain cease to be solid so Buckaroo could drive a car through it), and an issue of the World Watch I fanzine was dedicated to physicists explaining how such a thing could work. I doubt that RTD read that fanzine, but that's not the point; at least according to a selection of mid-80s physicists who are also sci-fi fans, there are scientifically plausible ways to do it.


 * Is there ever an explanation given for why the Daleks needed these specific planets to build their weapon? If any old planet would do then it would be incredibly stupid to abduct inhabited planets that would easily be missed, especially by the Doctor. What is special about the planets the Daleks took that makes them the only planets that could be used?


 * They could probably make their weapon without the planets, they need them to transmit the effect of the bomb right across reality - it's likely that otherwise the bomb would have a limited range. Those particular 27 planets would work together like an engine to transmit the signal. Think of it like a jigsaw puzzle, in that only the needed pieces can make the picture you want, and other pieces wouldn't work with the image.


 * Why did the Daleks need to invade and conquer the Earth if all they needed the humans for was one experiment? Launching a surgical strike on some poorly defended country could have gotten them plenty of humans without having to expend resources attacking everywhere else.
 * There are lots of Daleks, so one planet might be their idea of "surgical strike", plus the weapons wielded by humans don't pose too big a threat to Daleks : extending the attack to the whole planet isn't that big of a cost in terms of ressources compared to the potential gains (although if I was part of any alien race in the whoniverse, I would certainly avoid invading England).


 * The idea of the other Doctor growing a TARDIS is so stupid. How can Donna work it out if the Time Lords haven't in their millennia of power? Wouldn't the other Doctor already know it is possible to grow a TARDIS within a human lifetime if the original Doctor knew? It is good that stupid scene for the fanfic writers was cut out.
 * Well, first of all, the scene was cut, so the logistics of it don't really matter. But second, Donna explains that she is able to figure out things that the Doctor could not because she has the spark of human ingenuity in her mind, which the Doctor lacks. And third, just because the Doctor doesn't know how to do something doesn't mean that the other Time Lords did not. The Doctor was a terrible student who "scraped by", after all, so he may very well have just skipped class or not payed attention or something when they were teaching about increasing the growth rate TARDISes.
 * Donna is apparently getting the Doctor's knowledge. She would still have to learn information on TARDISes.


 * Why doesn't the Doctor at all criticize Rose for her actions. She clearly states she tried coming back to her world before the barriers broke down, despite the fact she risked destroying both worlds?


 * How did Rose appear on the screen in Midnight, centuries into the future?
 * Presumably whoever is controlling her jumps has some way of finding out where (and when) the Doctor will be. Otherwise, how would she have been able to find him at all?


 * How can the Reality Bomb reach EVERY universe? If a parallel is created for every decision we make, there must be an infinite amount. One person can create millions in just one minute, based on the number of decisions a person can make, and that has to be multiplied by the trillions upon trillions of life forms at any given point. In addition, the Void is void of matter. If the Reality Bomb destroys the links between atoms, then theoretically it wouldn't be able to effect anything in the Void, creating a sort of shield between the universes. Answering my own question: it's fictional.


 * How come the Daleks can speak English after the meta crisis Doctor flew off, I mean the ones on the crucible with Davros including Davros himself, because I dont expect they speak English, plus the Doctor himself so wouldn't they be speaking in their own tounge?
 * The Daleks and Davros have the ability to speak English (as is seen before the Doctor shows up in the first place) and may do that so that the humans know what they want. The Doctor has to be able to speak English or else any TARDIS-less episode would have him speaking Gallifreyan, which would be disastrous for the audience.