Theory:Doctor Who television discontinuity and plot holes/City of Death


 * It's very unlikely a Human could withstand the earth's atmosphere 400 million years ago, yet Duggan, the Doctor or Romana do have a problem standing outside at that time.
 * Duggan, maybe, but the Doctor and Romana being Time Lords likely could. Another possibility is that the TARDIS was protecting them as well.


 * How does the Doctor twice manage to direct the TARDIS to a specific point when the randomiser is installed?
 * The sentience of the TARDIS has been long established, too, so it might have known to bypass the randomizer.
 * The Doctor does have the capability to bypass the randomiser if he chooses to do so.


 * If the Countess has managed to go her entire married life without discovering that her husband is really a cycloptic, green-tentacled alien then either his skin suit is incredibly sophisticated to hold up to such intimate scrutiny, or their marriage is unconsummated.
 * Both are possibilities. It was only ever a marriage of convenience, and some aliens [including the Slitheen] have been seen to possess the ability to use "fully functional" human bodies as disguises.


 * Also, she's an upper-class British woman who married a rich continental Count because of the gifts he bought her. How much intimate scrutiny is involved in lying back and thinking of England while doing your wifely duties under the covers with the lights off?


 * Alternately, given the mores of time, she may have willingly entered a sexless marriage, assuming the Count was gay.


 * Life had already started 400 million years ago.
 * Maybe in the Whoniverse, the Silurian extinction event was more complete than in ours, and life had to be restarted. Or one of the earlier extinctions. Or the Time Lords sterilized the Earth 2 billion years ago because they predicted humanity would become a threat. Or life just never started naturally on Earth in the first place. Or whatever. Remember, the Whoniverse is not our universe—a planet that formed around the Racnoss spacecraft might not be exactly the same as one that formed through natural planetary formation, and the fact that it just happens to look pretty similar in 1979 could just be coincidence or convergent evolution or morphic fields or whatever.


 * In episode four Romana wires up a British three pin plug in order to connect Scaroth's time equipment to the (French) mains.


 * In episode one, the wrist of Scaroth's monster glove flaps about.


 * The sketch of Romana is different when it's seen outside the café from the one seen inside (and just who's doing the sketch, and why?)


 * The chances of there being solid land for them to stand on Four hundered million years ago are very unlikely.
 * Why? The Earth in the Devonian period had about 50-80% as much land surface as the modern world (although ironically, back in the 1970s, some people still believed it was a greenhouse drowned-earth age), and much of that land was part of large continents just as it is today.


 * Trapped within a bubble of accelerated time, without food and water, the chicken should just die before it has a chance to mature. Kerensky would not have time to reach old age before dehydration set in, either.
 * It is stated that anything in the bubble moves backwards or forwards in its "life cycle". This may just mean that it grows older or younger rather than literally living out its life faster.


 * Scaroth's device to refract the security lasers causes them to bend into the wall. Since this would still result in breaking the beam, it would set the alarm off as surely as sticking a hand between them.