Theory:Doctor Who television discontinuity and plot holes/Attack of the Cybermen


 * How did the Cybermen get into the TARDIS before the Doctor arrived.
 * The Cybermen might be advanced enough to break into the Doctor's TARDIS. It's also possible that the Doctor simply forgot to lock it, which he's done in the past.


 * Why do the Cybermen let the Doctor tamper with his controls when they are holding Peri?
 * Odds are they aren't familiar enough with the TARDIS to realise that the Doctor could tamper with its circuitry from the room they locked him in.


 * Your answer does not address the correct issue. The question was in relation to when they were all in the console room.  The Cybermen hold Peri.  The Doctor rushes to the controls to start the destruct count down.  The Cybermen could have stopped him, but they didn't.


 * It took the Doctor only about three seconds to jump away from the Cyber-Leader and set the self-destruct. The Leader was looking away when he did it and didn't notice what the Doctor was doing until it was too late, while the other Cybermen were busy holding Peri, Lytton, and Griffiths hostage. And depending on whether or not this takes place after the events of Earthshock, the Cyber-Leader might believe that the Doctor wouldn't be able to do anything dangerous with the controls, seeing how the Fifth Doctor didn't do anything of the sort in that story.


 * It is established that the Cybermen went to Telos after Mondas was destroyed to use the freezing chambers. So why are there Cybermen in the freezing chambers in this story? They haven't come there yet.
 * Yes they have. They have been on Telos for ages. The ones we see in the beginning are probably survivors from The Invasion who have somehow got in touch with the rest of their kind.


 * Actually, it is clearly established that the Cybermen on Earth have travelled back in time to 1985. The Doctor is concerned that the Cybermen have discovered the 'secrets' of time travel, to which Flast (while they are both captive on Telos) assures him that they have only captured a time vessel, but that they don't understand why or how it works, just that it does.


 * It seemed like a very crude plan for the Time Lords to send him to stop the Cybermen against his will, without him knowing what he has to do?
 * He has been sent on this sort of mission before (TV: The Brain of Morbius).


 * Cybermen can not feel emotions, meaning they can not laugh, so when the Doctor threatened not to co-operate if Peri is killed and a Cybermen told him they'd kill him if he didn't, that Cyberman smirked when they said they'd still have his TARDIS.
 * It may simply be a reflex action. We've also seen that Cyber-conditioning is not perfect.


 * The Cyber Controller has a bit of a tummy on him.
 * He also has a larger than usual head. Both may be designed to hold extra circuits or wires that make him a Controller instead of your average Cyberman.


 * The Cyberman guarding the Doctor and Flast tries to extinguish his flaming arm by batting it with his gun.
 * Yes, that's an accurate observation. But how exactly does a Cyberman's lack of knowledge on 'how to resolve a fire emergency effectively', constitute a discontinuity or plot hole?


 * The Cyberman's head that the Doctor investigates, searching for the distress signal, contains no organic part.
 * It does at least have a silver chin, a nice piece of continuity.
 * Remember that the Cryons have been sabotaging the tombs; the cryostasis system in that cell seems to have failed, and any organic parts of the Cyberman would probably have rotted away.


 * Towards the end, when a Cyberman realises that Cyber Control is soon going to blow up, he makes 'leg it' motions to his companion.
 * Yes. This is one of the benefits of the humanoid form. They have a richer choice of communication modes than for example a Dalek. Is there some reason they shouldn't make use of these options?


 * Why does the Doctor berate himself for misjudging Lytton when they didn't even meet in Resurrection of the Daleks ?
 * An untelevised adventure, perhaps?
 * And is he really that nice anyway?
 * The audience knows how nasty Lytton really is, but the Doctor only has this story (and a brief sighting of him in Resurrection of the Daleks) to judge him on. On that basis, the Doctor's comments make more sense, even if his conclusion is a bit hasty.
 * To add to the above, the Sixth Doctor was often given to over-dramatisation.
 * The Doctor and Lytton did meet in Resurrection of the Daleks. They met on board the Dalek spaceship, where he was clearly a Dalek agent and therefore not someone the Doctor would readily trust, and Lytton later fired at him twice in an attempt to kill him at the warehouse, another reason to have a low opinion of him. There's also a good chance that he questioned Stien about who Lytton was off screen once they were allies.


 * Why is Lytton's distress signal still transmitting some months after the Cryons have made contact?
 * How do they do this, given that they are in the future?
 * He may not have know it was, or may not have been able to (or had a chance to) deactivate it. Alternatively, he may have hoped for another additional (or better) option.


 * How was Lytton able to build a sophisticated communications system with 1985 components?
 * How was >= 1986 technology developed? With new knowledge and <= 1985 components. The know-how is probably beyond the average futuristic mercenary, but then again, Lytton is far from average.


 * Why does Lytton abduct Griffiths when he could have taken his policemen with him?
 * If Lytton intended piloting the time travelling machine, apparently he needed a crew of at least two more. The 'policemen' might have been a consideration, but perhaps he needed people just a little more intelligent.


 * How can you turn a comet (a large snowball) into a bomb?
 * You don't have to actually turn it into a bomb. Just steering it into Earth would leave the planet in such a bad state that they wouldn't be able to organise any sort of defence against Mondas the following year.


 * You collect a rare mineral, one which is completely inert at temperatures below zero, and you carefully seed a calculated area of the comet with it- probably the solar-facing side. As the comet falls sunwards, it heats up- generating the iconic comet's tail - and once that mineral reaches the right temperature, it self-ignites, pushing the comet sharply off course at the right moment to slam it into Earth.


 * Why do the Cybermen want to destroy the surface of Telos?
 * I believe it was mentioned in the story that they wanted to study the effect for research purposes.


 * Why do they leave the Doctor in a room full of explosives?
 * If you paid attention to the episode, the Cryon that the Doctor was locked with said that the Cybermen left the explosives there, because they were useless in temperatures below 0, and the Doctor was locked in a freezer. The real question is why did the Cybermen let him keep his sonic lance (probably a simple oversight).


 * There's at least one Cyberman left in the TARDIS.
 * Not necessarily - it might have left the TARDIS in between its arrival on Telos and the Doctor reclaiming it. A better question might be why it isn't better guarded, considering what a vital asset it would be to the Cybermen.


 * And even if it is, that's not necessarily a plot hole. It could have wandered around the TARDIS for decades until dying, or escaped later when no one was looking. Plus, with Kamelion dead, the Exxilon and the leftover Earthshock Cybermen needed a 4th for their nightly bridge game.


 * The Foreman junk-yard doesn't resemble either the version seen in An Unearthly Child or Remembrance of the Daleks.
 * However, the story takes place in 1986, at least 23 years after the events of those stories, and as such the junk-yard could have undergone any number of physical changes or even relocated in that time.


 * How can the Cryons exist at all? They are a species that can't survive temperatures above 0, but they evolved on a planet where the temperature IS above 0. Why did they evolve in a way that doesn't let them survive in their environment, and how did they survive before developing refrigeration technology?
 * The answer lies in your question. If they've always been the same, then they never really evolved at all! There could be a number of permutations. Quite probably at some stage there may have been an ice-age on Telos. The Cryon's may have developed their technology to stop the ice-age from ending, or to facilitate expansion out of the colder areas they were previously confined.
 * Seeing how we never see any Cryons on the planet's surface, it may well be that the planet's interior is colder than the surface - we've seen at least one other such planet, namely Spiridon - and thus more hospitable to the Cryons.


 * When the Cybermen storm the TARDIS at the end of episode one there are four Cybermen: the Cyber Leader, the Cyber Lieutenant, a standard 'silver' trooper, and a 'black' stealth. However in episode two the four Cybermen now consist of the Leader plus three 'silver' troopers. Where did the black Cyberman go? He's never seen again for the rest of the story.
 * He may have stayed behind when they left. Otherwise, see the related question above


 * He's a Stealth Cyberman. In the seconds between the end of episode one and the beginning of episode two, he disguised himself as a silver Cyberman.


 * Russell's body vanishes after the cyber leader threatens Peri.


 * This is the Doctor's TARDIS. If it didn't have some kind of off-screen facility for quietly tidying up clutter, then the TARDIS crew would never get to have any adventures, because he'd have lost the main doors behind the accumulated junk centuries ago.
 * For a more mundane explanation, some of the rank-and-file Cybermen may have simply picked up Russell's body and thrown it out of the TARDIS while the Doctor and Cyber-Leader were talking.