Theory:Doctor Who television discontinuity and plot holes/The End of Time


 * When the Doctor arrives at the Prison following the explosion, couldn't he have just arrived at an earlier point in time?
 * He appeared to have tried extensively to get there before, given the concurrent sequence with him in the TARDIS; destiny and/or the TARDIS had other ideas. However, by arriving just a few hours later, he became part of events. Therefore, he could not go back because now he is part of the history; he saw he never stopped the Master's rebirth so must stay and deal with the revived Master instead.


 * The Doctor told Wilf that once he dies his body cannot regenerate but this statement contradicts the 7th Doctor regeneration into 8th, because at the time of the regeneration, the 7th Doctor was declared dead.
 * It also contradicts Incarnation 3 to 4. I believe Doctor 3 actually dies!
 * And Doctor 12 stated that if the injuries are too bad he won't regenerate, but those doctors (3 and 7) already died.
 * He's likely wrong then, plus this incarnation is really sensitive to death, having aborted a regeneration to keep his face.
 * I think every incarnation is sensitive to death!
 * If the Doctor were able to regenerate even if he died then Time Lords wouldn't be able to die before they got to their 12th regeneration?
 * Not sure I understand your statement. The Doctor has died. 3 to 4, but he was given aid.


 * Wilf tells the Silver Cloak the Doctor wears "a brown suit, sometimes a blue suit" however he's only met the Doctor 3 times, once wearing the blue (Sontaran Stratagem), once wearing the brown suit (Journey's End) and his tuxedo (Voyage of the damned). On his part it seems like a pretty sweeping statement to say he always wears the same thing.
 * Donna may have told him he predominantly wears brown, pre losing her memory.


 * When the Time Lords are walking to the council chamber they keep changing size. One moment they only just fit on the bridge next they have a little more room and then one has a little room and the other is basically on the edge again.


 * If the Doctor knew that anyone entering the chamber to save Wilf would die from radiation, why could he not run to the TARDIS and pick up Captain Jack from the space bar and ask him to go into the chamber instead (a-la "Utopia")...?
 * He can't do that.
 * Firstly it wouldn't be nice to leave poor old Wilf all on his own at a time like that.
 * it would be unfair to use Jack like that.
 * Also he could enter and absorb the radiation where as Jack couldn't meaning the radiation would spread when Jack left the chamber.


 * How can the Time Lords on the last day of the War be aware that they've been time-locked?
 * The Time Lords themselves may have time-locked the Time War.
 * Even if the Doctor did it with the Moment, they may have known or guessed how the Moment worked well enough to know that it would time-lock them.


 * Why wasn't anyone surprised at Rassilon's appearance?
 * Time Lords recognise other Time Lords. The Doctor knew Rassilon, from the Time War and previously. The other Time Lords already knew the Lord President was Rassilon, hence no surprise.


 * How did Miss Trefusis time-travel to the end of the universe, where the Master's ring was located? How did she time-travel back to Earth? How did she know that the Doctor would leave the ring there?
 * The Master had hundreds of contacts, many that the Doctor didn't know about.
 * Also, the Doctor didn't cremate the Master in the year 100,000,000,000,000; he did it in a disused area or quarry that just looks like Malcassairo.


 * When the Master is restored to life, it is with a growth of facial hair, which he did not have prior to his death.
 * He had stubble when he regenerated into the Harold Saxon version of the Master, so arguably he is simply returning to the "default state" of this regeneration.


 * If Lucy has been in prison for approx. a year, how could the Master's DNA still be on her lips?
 * It's demonstrated in TV: ‘’Smith and Jones’’ that a quick kiss is enough for a genetic transfer. Presumably, since the Master kissed Lucy many times, the genetic transfer lasted long enough for it to be cultivated at a later date. The Master was clever enough to keep a portion of himself alive in the first place he could have also ensured DNA remained on Lucy's lips.


 * Both Lucy's voice and personality seem dramatically different.
 * Since Lucy has been in jail she has had time to think about her actions with the Master, and has seen how evil he was. Arguably, the first inklings of this "new" personality occur as far back as TV: Last of the Time Lords when she shoots and kills the Master, with the implication he had abused her during the year that never was. It is also stated she was under "the Master's spell" meaning she believed what she was doing was right.


 * When talking about their previous encounters, Wilf mentions his paintgun although the Doctor wasn't there when he shot the Dalek.
 * It's possible that Wilf informed the Doctor of his encounter with the Dalek while they were waiting for Donna to awake in TV: Journey's End.
 * Wilf is the one who mentions it, and he was there. The Doctor doesn't respond to the reference.


 * It is said that Martha is married to Mickey but isn't she supposed to be married to Tom Milligan?
 * It was established in TV: The Sontaran Stratagem that Martha was engaged to Tom and later it was stated in TV: Children of Earth: Day One that she was on her honeymoon. However, it is not stated as of who she is with. She may have been just married to Mickey and on her honeymoon with him.
 * Her relationship with Milligan obviously ended at some point and she ultimately married Mickey. The episode does not indicate when the Doctor found them - it could have been years later
 * The audio story Dissected stated that Martha split from Tom, though she didn't mention why.


 * Why did the TARDIS explode during the regeneration scene? This hasn't happened before.
 * Regeneration is unpredictable, and some are more violent than others.
 * Alternatively, since he has held the regeneration back for an extended period of time since exiting the radiation chamber, it all blasted out of him at once, building more force the more it was held back.
 * The radiation the Doctor was exposed to could also have made the regeneration more explosive.
 * There is strong evidence that, unlike past regenerations, the Doctor delayed the change for an extensive period of time, long enough to not only visit the companions shown on screen in Part 2, but also, as revealed in TV: Death of the Doctor, visit every one of his past companions. The pent-up energy from the Doctor delaying his regeneration could well explain the violence of the change.
 * I support your statement, is like you fill a balloon with air and you keep filling it until it explodes, that's what happened with the Doctor he delayed the regeneration so much that when he finally released it , it was very violent.


 * If the regeneration was violent enough to destroy the TARDIS, why did it not at least rip his clothes?
 * Because the energy was shot outward from his body, instead of going inward.
 * Also, his clothes were "raggedy", a fact that was commented on repeatedly in the following episode.


 * Why did the Doctor choose to meet Verity Newman, a descendant of Joan Redfern, and not Redfern herself?
 * The Doctor has already caused Joan a great deal of heartache and he likely does not wish to reopen old wounds.
 * As TV: Death of the Doctor establishes more visits than those shown on screen, we don't know that he didn't.


 * If the Doctor saw Rose from 2005, wouldn't that create a paradox due to the fact Rose has not met the Doctor yet?
 * The Doctor stayed in the shadows at the end, not wanting Rose to see his face. She asked if he had been drinking, so she would have dismissed him as a drunk and likely not remembered him from the incident. Just as in TV: Smith and Jones, it is safe to do "tricks" like this that don't affect the timeline.


 * The room with The Gate was shaking because of Gallifrey coming closer, but then it stopped shaking when the Doctor picked up the gun. Why was this?
 * Gallifrey had reached some manner of "equilibrium point" in its approach to Earth.


 * In TV: Smith and Jones, the Doctor clearly states that he can expel radiation from his body if he focuses hard enough, so therefore why does he need to regenerate?
 * The damage has been done.
 * There is a misconception that all radiation is the same. In reality, there are several types and, as shown in several stories (TV: The Daleks, The Mutants, Planet of the Spiders etc.), alpha and beta particle radiation is lethal to Time Lords (to a lower extent) while what's in the electromagnetic spectrum is near harmless to them (i.e., Gamma rays, Ultra Violet, X-rays etc.).
 * Even if it were exactly the same type of radiation, he absorbed billions of times more radiation in this episode.
 * Furthermore, the Doctor was already in a weakened state after surviving the fall from the mining ship.


 * How did the Doctor survive jumping out of a moving spaceship, crashing through the skylight, and landing on the marble floor? A lesser fall onto grass killed the Fourth Doctor.
 * Physically, each Doctor is different and can be expected to be more or less durable than the others. In addition, the Tenth Doctor mentions he can survive a fall of at least thirty feet in the episode TV: The Satan Pit. Plus, he was also in the same room as the gate, which prevented him from dying, but not healing his cuts as he wasn't inside the gate.
 * Additionally, the Doctor planned his fall here, whereas his fall in Logopolis (TV story) was unplanned. Crashing through the skylight would also have somewhat broken his fall.
 * Though views on its canon status may vary, the Third Doctor survives a fall from roughly 200 or so feet by what he calls "bone compression" in the BBC radio drama The Paradise of Death. Granted, that survival causes him to fall into a brief coma where he's believed to be dead...


 * When the Doctor decides whether to shoot the Master or the President he holds the gun in different hands (left when pointing at the Master right when pointing at Rassilon).
 * You can see him change hands.


 * When the Doctor is aiming the gun at both the Master and Rassilon, you can see (and hear) that he has quite obviously pulled the trigger on each occasion.
 * The Doctor is holding the trigger close to the point of shooting a bullet: as he changes targets, he changes hands where he is holding the trigger closely to the point of firing each time.


 * If Rassilon's glove is so powerful why would he hesitate to use it when the Doctor points a mere revolver at him?
 * Even if he did fire, the Doctor would have time to fire as well, killing them both and destroying the link.


 * After the Doctor hits the Sontaran the scene cuts from a close-up shot to a full-body shot. However, no Sontaran is visible in the full-body shot.
 * The Sontaran fell off of the platform the Doctor was on.


 * Wilfred states that the Doctor mentioned regeneration to him during a previous encounter, although no such scene appears in previous episodes.
 * The Doctor did however explain Donna and the "Meta-Crisis" to Wilfred and Sylvia. This virtually necessitated at least a simple explanation of regeneration.


 * Why weren't Earth and Gallifrey both ripped apart immediately by gravitational forces when the latter materialised in such close proximity?
 * Gallifrey hadn't completely materialised yet, so it hadn't become solid enough for its mass to completely destroy the Earth.
 * Also, Time Lords have some pretty impressive gravitational engineering. If they can keep a supermassive black hole (or least the singularity from the middle of one) in the basement of the Panopticon, this is child's play.


 * The Doctor recognised that the person that was aiming a gun at Wilf was a Vinvocci for being 1 inch taller, suggesting that all the Masters were the same height, but when Joshua Naismith and his daughter changed, it is clear that the Joshua Master is taller than his Master Daughter.
 * In the scene where the Master taunts the Doctor of his newly created "Master Race", you can clearly see that both the Joshua Master and Abigail Master are the same height. In prior scenes where they were different height, the transformations wasn't yet complete.
 * Abigail Master is wearing high heels, but his head is at the same height as Joshua Master; therefore shorter.
 * Or he kicked them off. Those things reportedly aren't very comfortable. Once the transformation is complete, all the "Master Race" (* sigh* ) are the same height.
 * No, you can see he's wearing heels.


 * The Doctor "has" to sacrifice himself to save Wilf by going into the malfunctioning radiation chamber. Yet while he is speaking to Wilf, the shot shows a fairly obvious gap between the door and the rest of the glass chamber. This makes his sacrifice seem a bit of a waste, as the door could have easily been opened (by force or otherwise).
 * The Vinvocci glass contains and absorbs the radiation, and trying to break open the door would have just caused the radiation to flow out from that unlocked chamber instead of into a locked chamber where it could be contained. This is why the doctor must switch the active chamber to his own.
 * He even explains this in the scene, when he says that even using the sonic screwdriver would be enough to have that effect.


 * The Doctor has gone through 10 regenerations (if you do not count the meta crisis one.) Some Time Lords had control over the process. If the Doctor has gone through this many, why has he not gained any control over the process?
 * Some Time Lords can control it better, just as different people have different strengths and weaknesses.
 * Additionally, the Doctor usually regenerates under extreme circumstances, giving him less control over the process.
 * In this case, he also held off regenerating for a significant period of time after being healed, which one would expect took much of his focus and control.


 * Luke (and by extension Sarah Jane and the rest of her team) are aware of the "Master Race" transformation, despite the fact that it occurred simultaneously for everyone involved, making outside observation of the effect impossible. Since everyone changed all at once, and then changed back, nobody could have observed it.
 * Luke may have been immune due to his unique biochemistry. Regardless of that, there was also recorded visual evidence from news cameras, security footage, etc.
 * The transformation would also have been witnessed by Mr Smith and K9.


 * Luke reacts to the Doctor as if he's never met him in person before, even though they would have met during The Wedding of Sarah Jane Smith. His cut off line appears to be "It's you! You're the Doctor.", which would be odd since they'd already met before.
 * Luke clearly recognises the Tenth Doctor's face from their previous encounter, and he was in shock of him appearing out of nowhere, saving his life.


 * If the woman who speaks to Wilfred is a Time Lady, (she is seen with Rassilon on Gallifrey during the Time War), and the Doctor was said to have destroyed every Time Lord and Dalek in the war, how could she meet Wilfred? If she is dead, exactly how could she return and come to see Wilfred?
 * Her "leaking out" of the time lock as an apparition to appear to Wilf is somehow connected with Rassilon's link. Exactly how that works is intentionally left unexplained.


 * Donna's defence mechanism was able to knock out all of the Master race that was after her, yet when would the Doctor have had time to implant this if simply hearing about anything that happened with him would kill her?
 * The Doctor probably implanted it at the same time as he was wiping her mind.


 * Why didn't Donna die? She saw a flashback of the Doctor from DW: The Runaway Bride, and the Doctor specifically told Wilf that if she remembered him, she would die.
 * She would die. The defence mechanism which knocked her out would not work indefinitely, and he may not have known it would work at all. Technically her mind did "burn up".


 * Why does Wilf have a revolver? Only officers carry revolvers, yet he claims he was a private.
 * At the front only officers carry revolvers in the British Army. A private being issued a revolver at some point is perfectly reasonable.
 * Or, he might have bought it war surplus years ago.


 * The Doctor states he can tell if a Time Lord is around, so how does he not sense the woman whenever she appeared to Wilf?
 * She was just an apparition.


 * Before the Doctor regenerates he clearly must be using some sort of hair product, why wasn't his hair sticking up after his regeneration?
 * The Doctor's body changes completely so any hair product, if any (who knows what the hair of Time Lords can do), disappears with the old hair.
 * When the First Doctor regenerated into the Second, his clothes changed as well. The same was apparently true for Romana (although that happened off screen). If clothes can be changed and TARDISes set on fire, hair gel can presumably be dissolved.


 * When Rassilon kills The Partisan, she is destroyed immediately. Why would it take less time the first time, but not as quick the other times?
 * Much of the functioning of the glove is unknown. Despite this, it did take several seconds from the time he stood up till he destroyed the dissenting Time Lord. This appears reasonably consistent with the later scenes.


 * What was a baby Adipose doing alone at the bar without its parents?
 * Without knowing much of anything about the Adipose life cycle other than their creation, a great many possibilities exist - including that this was not necessarily a "baby" Adipose. Who is to say that Adipose looked different when they aged?


 * The Master sometimes used his energy bolts, and his flesh disappeared. Yet other times his flesh didn't disappear. Why would this happen?
 * When he used the energy bolts before, his flesh disappearing is most likely to be a coincidence.


 * The Doctor mentions the Nightmare Child in a list of horrors born in the final days of the Time War. However, in The Stolen Earth, the Doctor said Davros's command ship flew into the jaws of the Nightmare Child in the first year of the Time War.
 * It is possible that the Nightmare Child lasted throughout the Time War and the Doctor mentioned it because it was a good example of a great horror of the Time War.
 * Also, by the nature of a Time War, something created at its end might be present at its beginning.


 * Not necessarily a discontinuity requiring explanation, the High Council of Time Lords is revealed to be an enormous body (resembling the Senate in the Star Wars sagas). In earlier stories the Council was quite small, consisting of the President, Chancellor, Castellan and a few other high-ranking Timelords and Timeladies.
 * The Council consisting of the President, Chancellor, Castellan and a few other Time Lords that appeared in the Classic Series and the first scene of this episode is the Inner Council, while the Council resembling the Senate is the High Council which according to DWM Issue 100 is equivalent to a Parliament.


 * When the Doctor enters the TARDIS after hearing the Ood's song, his right hand starts to glow with regeneration energy. But when he walks around the console, the glow is gone.
 * The regeneration was just starting, and the Doctor was still putting it off until after he got the TARDIS away from Earth - i.e., the energy causing the glow was ebbing and flowing until he couldn't hold it back anymore, making the appearance and disappearance of the glow perfectly consistent.


 * The platform Rassilon uses to speak to the High Council changes shape completely from Part One to Part Two.
 * Those were two different times he was speaking, hence two different platforms - one a long plank before the vote was taken, one a hexagon after the vote was taken.


 * When the Doctor alternately threatens the Master and Rassilon with a revolver, both have time and the means to kill, maim or disarm him. Why don't they? And why does the Doctor think a mere bullet could kill the mighty Rassilon (who presumably would regenerate if he was killed) anyway?
 * The Master clearly no longer intended to kill the Doctor, and Rassilon wanted to give the Doctor a chance to join him. If the Doctor had shot Rassilon in the head, it would have killed him, and we don't know if Time Lords can regenerate from that kind of death.
 * He didn't even necessarily have to kill Rassilon; just knocking him into a healing coma may have been enough to break the link.


 * The Doctor was resisting regeneration. When the Master did it, he died. Even though seeming to resisting regeneration would cause killing, why did the Doctor not die?
 * The Doctor delayed the aspect of regeneration which resulted in his physical change, however he had already healed. The Master had refused to allow his body to even begin the healing process, therefore he died from his gunshot injury.
 * Alternatively, the Master's and the Doctor's holding-back could be different; the Doctor may have merely belated it, the Master committing suicide.


 * When Wilfred goes to help the technician out of the Nuclear Bolt room, the technician is showing the effects of the Master's template; however, when Wilfred goes in, it heals.
 * The Doctor stated that he had to filter the levels before the chamber could be used to cure Wilf of the vision of the Master.


 * The Doctor was seemingly acting evil when deciding whether to shoot the Master or Rassilon. Wouldn't this make the future where The Valeyard exists concrete?
 * He wasn't acting evil. He simply seemed willing to go to the extent of killing one of them in order to save all of creation from Rassilon's "final solution".
 * Remember that the Doctor already "used the Moment" to wipe out the entire Dalek and Time Lord species (at least as far as he knew). If you can accept that as the lesser of two evils, accepting shooting Rassilon as a possibility seems pretty easy.


 * How did the Doctor put off the regeneration for so long? Isn't regeneration supposed to happen immediately? With the Doctor putting it off that long it seemed as if the damage had been repaired and he wouldn't need to regenerate.
 * Taking the points in order: The Doctor put off his regeneration so he could say goodbye to his friends. Regeneration does not always happen immediately, it depends on the manner of death, how much damage is done, and how quickly. And the damage was not repaired; Some of the initial regeneration energy healed the Doctor's cuts, that's all.
 * According to some novels (again of questionable canonicity) the lag between the massive radiation dose the Third Doctor was subjected to in Planet of the Spiders and his regeneration at UNIT HQ may have been as long as 10 years, so there may be a precedent.
 * There is also a real-world human analog to the prolonged death. Actual radiation poisoning can exhibit a stage known as the "walking ghost phase;" this is a phase in which enough of the body's internals are damaged beyond repair and the victim's condition is terminal, but the victim does not feel the full effects and suffer the ensuing death for some time.


 * If the tracking on the asteroid lasers is automatic, the only thing required of the gunner being to "deploy the trigger on the joystick", then what is the point of the gunner?
 * Perhaps the point of this is so that the gun can be fired when it's aiming at a particular point, which the automatic tracking can't identify.


 * The Master is a Time Lord, why does his pattern in the Immortality Gate even work on humans? Why only on humans, why not the Vinvocci, why not on the Doctor, the only other Time Lord on Earth?
 * The Master did reprogram the Gate. He made it work so it would affect only humans, perhaps he didn't take the others in the account, perhaps he wanted or needed The Doctor to survive. And obviously he programmed it so it would copy his own DNA.
 * He didn't know of the Vinvocci intruders at that point, and due to his amusement to the Doctor's shock. He would probably consider it boring to turn his worst enemy into just another copy of him.


 * When the Doctor pulls out his sonic screwdriver and says 'even this will destroy it', it has three prongs like the Master's laser screwdriver, when the sonic has only one?
 * It doesn't. It's a trick of the light. It's the same screwdriver.


 * It has been stated in various sources including by Russel T Davies, Julie Gardner and John Simm himself that the Master's hair is definitely blonde in this story. The explanation for why his hair was blonde was that he needed to alter his appearance since he looked like former Prime Minister Harold Saxon. However, when he enters the Immortality Gate and transforms every human into anther Master they too have bleach blonde hair. If their DNA is being changed to transform them into all into Masters how can they possibly have dyed hair since hair dye isn't a part of the Master's genetic make-up.
 * The Master would not have cared if he still looked like Saxon. The most probably explanation is that the change of hair colour was by changing his DNA.
 * No one has confirmed that the Master's DNA changed to allow for the change in hair colour. I believe in a podcast the executive producer refuted the claim that his hair has changed by any means other than hair dye (they note that the root of his hair hasn't changed). Since we don't have any better explanations, it could be that the trauma of the Master's botched resurrection coupled with Time Lord Regeneration abilities (and the fact that he is dying/aging) has caused his hair to strangely change to blonde (I say strangely because the roots are not blonde). RTD has stated that the Master elected to change his hair colour since he looks like Mr Saxon, so perhaps he achieved the change through a conscious effort at manipulating his artron energies to force the change (a kind of small-scale controlled regeneration; it is shown he can manipulate his energies to fire lightning bolts so why not). This effort might be difficult to sustain and/or painful thus why it isn't more extensive (i.e. why he doesn't just change his entire body to avoid recognition)


 * It is established here that the Master has indeed heard "the drumming" throughout his life, since he was a boy on Gallifrey. Yet he never mentioned it nor gave any indication of it prior to being Professor Yana.
 * It's of course possible (although admittedly unlikely) that he never mentioned it to the Doctor previously, despite being best friends/enemies for so long.
 * Or the fact he said it was getting louder. So maybe The Master had never really got bothered by it that much.
 * And the third possibility is that he _did_ mention it before, but it just never happened to come up on-camera. When people have chronic tinnitus, they stop asking everyone "Do you hear that ringing?" after a few weeks, and from then on it only comes up when they're talking about their health.


 * The Time Lords seems to know that the Master hears "drumming", even before they decide to send the signal back to him as a boy (and therefore that they are the cause of it). Yet the Doctor showed no recognition of it when Professor Yana spoke about hearing drumming in TV: Utopia.
 * It's of course possible (although admittedly unlikely) that he never mentioned it to the Doctor previously, despite being best friends/enemies for so long, and the high council knew about it through other means not available to the Doctor.
 * It's also possible that during the Delgado Master era the drumming might not have been as noticeable, perhaps subliminal. And considering the Ainley and Roberts Masters were not actually Time Lords, but the Master inhabiting Tremas of Traken and Bruce the paramedic, the drumming may have manifested itself in a different way, if at all, only to return in full force when the Master was finally revived as a full Time Lord.


 * How come when the Master was brought back to life his hair is shorter and darker but later he has hair a bit longer and is blonde.
 * Its been a while, his hair's grown, and he dyed it.


 * How exactly did the Master acquire his powers?
 * It was down to a freak accident during his resurrection.


 * Is there a connection with Rassilon's glove and the resurrection gloves from Torchwood? They both look similar.
 * It's not impossible, but there's no reason to believe so other than the fact that they look similar.


 * How can the other Ood communicate without those Ood things? (Sorry forgot the name!)
 * Telepathic link. Time Lords have one, the Ood have one.


 * If the Doctor landed in the bar then events there would immediately coincide with events on Earth and it is made out Wilf is in imminent danger and knowing how often the TARDIS stuffs up with regards to precision landing i.e. Aliens of London where he messed up by a year it is likely wilfred could have died long ago and radiation spread out when he landed
 * You might want to rephrase this question (and please don't add it at the very top of the page next time; I moved it), because I have no idea what you're asking.
 * I think it wasn't meant to be question. I think it was supposed to be answer to the second point where there is stated question Why Doctor didn't go to catch Jack from the bar in order to save Wilf?

This one is kind of weird because I am answering my own question really. Wouldn't the sign of literally any alien, or piece of alien technology which would jog Donna's memory cause her to remember and die? Well I think the memory has to be actively pursued e.g. it isn't the case that if she met the Doctor and he doesn't actually properly try to remind her of their times together she will remember, after all she did meet him in the guise of John Smith in Journey's End. Equally encountering something like she would in her travels with the Doctor wouldn't cause her to remember necessarily because it would be all new to her. Only if she is being constantly reminded like an Ood popping up and saying remember me would that cause her to remember. The Doctor's defence mechanism cannot be healthy but he likely installed it should Donna ever remember so even if this does happen, she has some kind of defence. On top of this I theorise that while the Master had programmed the Immortality Gate to transform all humans in that moment into essentially duplicates of himself, Donna not being a human, but a Human-Time Lord Metacrisis (with her Time Lord consciousness and knowledge safely locked away), wouldn't be transformed by the Immortality Gate but since it isn't meant to target her DNA. however, she is part human so perhaps the intrusion of the Master's mind (which contains memories of the Doctor, Martha and the TARDIS amongst other things and lets not forget he himself is a Time Lord consciousness) into hers, which being part human isn't necessarily impossible (even if the effect wasn't as powerful) could have reawakened some of her memories and caused her to burn. thus Donna is essentially safe from further alien incursions (which have since the incident with Gallifrey rarely been on a large enough scale to warrant her attention) and should anything bad happen she has the defence mechanism to protect her at least temporarily.
 * When the Doctor visits Rose, she appears to have "new teeth," the same that she had in Series 3, but not the same she had from Rose (TV story) to Doomsday. Is it plausible that she had these teeth, got new teeth, had adventures with the doctor, and then somehow got back her old teeth. (Yes, I know the real world reason to why there different. And also, I would say her teeth are very noticeably different, there a different colour and everything.)


 * How is it possible that, when night is falling in England, that it is also dusk-like in Beijing? It should be 2am there.


 * Why doesn't the Doctor suffer terminal velocity when he falls so far from the spaceship, and smashes through a skylight?
 * Maybe the Skylight broke his fall?


 * Having not seen this episode for many years, is it explained how Wilfrid Mott is shielded from the Immortality Gate?
 * Yes, it's because he's inside the radiation chamber at the time.