Theory:Doctor Who television discontinuity and plot holes/The Ark in Space


 * If there are thousands of people on Nerva, why is there only 1 shuttle and a transmat with only 3 pads?
 * The Shuttle may be larger than what we see (note that the entire Wirrn swarm is able to fit aboard it) and there are probably more transmat pads throughout the station. Vira does say that getting everyone down to Earth via transmat will be a long task.


 * Why do they teleport to the Earth rather than take the TARDIS?
 * The TARDIS can be unreliable at times.


 * There is a piece of very poor editing done when the half-mutated Noah confronts Vira and the Doctor as they move along the corridor (probably done to remove the more grotesque aspect of the scene). Noah is still talking and then somehow the door slams shut, cutting him off. Yet it is not clear who does this or what exactly happened.
 * One of the three easily could have pushed the button to seal the door. Vira and the Doctor have a good motive for doing exactly that!


 * The people needed to use a device on their hearts to complete the revival - how would this have worked if no-one was around to help them with it?
 * It's not part of standard procedure; the system had already malfunctioned due to the Wirrn's interference.


 * The Wirrn falling out at the first cliffhanger interrupts the Doctor talking - but he's not talking at the start of episode 2.
 * Or we just don't hear him.


 * When Sarah is trapped in the control room, why is the switch for the door on the opposite side of the room?
 * Why not? All functions for the room are controlled from the console.


 * Once the auto guard has been switched off, the Doctor and Harry test it by sticking their heads out!
 * That's where their eyes were located. They heard it deactivate and were cautiously looking to verify.


 * The slime trail which the Doctor and Harry chance upon is clearly visible to the audience from the start of the scene.
 * The trail was supposed to be there. In the story the Doctor and Harry simply do not see it at the start of the scene.


 * Can all of the Wirrn really fit into that small cockpit?
 * Probably not, but the shuttle is larger than just the cockpit.


 * Why doesn't the Doctor want to wake everybody up and take them to Earth in the TARDIS? His reasons make it sound like he's just making the game more interesting.
 * Using the TARDIS to change events is something he usually shies away from. Plus, the logistical issue of waking them all up and getting them to the TARDIS would be challenging to say the least.


 * Several of the cyrogenic cells are empty, but there are no slime trails leading to them. With space at a premium it doesn't make sense to have empty cells, but the lack of slime trails means the Wirrn didn't take the bodies either. So where'd they go?
 * They are presumed to have been taken by the Wirrn. The slime trail simply isn't visible.


 * Why is the table screwed down to the floor? None of the other furniture is. Plus as the Doctor and Harry start to move the table there's no mounting in the floor where the screw was.
 * The table was apparently never meant to be moved, hence it was screwed down.


 * In the human-preservation chamber there are at least two levels of cells, but there are no ladders. How do the people get down when they wake up?
 * It is just possible that in the future humans have invented the lift.


 * Given how readily the Doctor used his sonic screwdriver as a thermal lance in the previous episode, and how readily it went through reinforced metal, why doesn't he cut a quick hole here to get some air?
 * We don't know the composition of this metal compared to various metals in previous episodes. And if the atmosphere on the other side contains high levels of oxygen, as would be expected, then creating sparks and fire is a bad idea.


 * The space station noticeably "wobbles" as it orbits above Earth in the opening shot.
 * Real space stations do "wobble".


 * When Vira climbs out of the cryogenic capsule, the styrofoam comprising the capsule sqeaks.
 * Do cryogenic capsules not normally squeak? Never having been in one from the far future, I can't say...


 * Without space-faring technology, how do the Wirrn launch themselves into space, and how do they avoid burning up during planetfall?
 * While I'm not sure how they reach escape velocity, re-entry could likely be accomplished by spinning a durable chrysalis/cocoon, or a mixture of spun, silken material and debris, similar to the approach of the Caddisfly larvae.

There is no one down on earth, like you said humanity is branching across the universe, the earth has been abandoned, and as shown in the next story, humans by this point think nerva is just a myth, so there is no reason for them to go back, to look at it.
 * While the suspended humans have been "oversleeping", the rest of humanity has supposedly been branching out across the universe. So how can Nerva simply have been forgotten? Surely someone down on Earth would have noticed.