Theory:Doctor Who television discontinuity and plot holes/The Twin Dilemma


 * The altered revitaliser machine sends Peri 10 seconds back in time, and thus... back to the TARDIS?
 * The revitaliser itself does not achieve this. However, the Doctor is fully aware that the TARDIS would detect any unusual time/space disturbance in its viscinity and redirect it to the control room for the Doctor to study (See Pyramids of Mars, The Awakening, Timelash, and The Greatest Show in the Galaxy, to name a few).


 * Why does Azmael bother with the 'Edgworth' alias?
 * Anything to help cover his tracks. He has just kidnapped two children.


 * Even if the purpose of Azmael using a false name is to to help mask the connection to Joconda, why does he also call himself "Edgeworth" in conversations with Mestor and Noma?
 * Time Lords have a tendency to adopt pseudonyms and then refer to themselves by the same.


 * Azmael keeps a slug-killing potion hanging around, but has never thought of using it.
 * It wouldn't have done anything if he did, since Mestor could shield himself from the attack. Azmael probably knew this, but since the Doctor didn't let him in on his attack plan, he never got the chance to warn the Doctor.

They may have reason to dismiss the idea of the true method, which was using a long-range transmat.
 * The twins believe Edgeworth's story that his teleportation into their living room is a conjuring trick.


 * Why do the kidnappers stop off on Titan 3?
 * Their ship apparently took some damage in the pursuit.


 * Peri makes no mention of the Doctor's heroic sacrifice on her behalf, nor thanks him for it (no wonder he's touchy).
 * Possibly a bit rude, but remember that she'd seen the man she knew completely transform into another one. That's bound to have thrown her off a bit.


 * She has a touching faith in the notion that, as a policeman, Hugo cannot be a homicidal maniac.
 * That might be a bit naive on her part, but police forces are generally careful about admitting people that might have murderous tendencies.


 * The twins' father is indeed being 'melodramatic' when he tells them that their mathematical skills could change events on a massive scale.
 * This isn't actually without precedent - it's appeared before in the form of Block Transfer Computation.

That would be a production error, not a plot hole.
 * Why does Mestor need the twins to produce calculations to stabilise the orbit of the smaller planets, when in fact it would run counter to Mestor's objectives (and, according to the Doctor, is actually impossible anyway)?
 * When Elena operates her monitor to check out the freighter, it's filled with a mass of text. But towards the bottom, it says, "Run", allowing the actress to press one key and activate the graphics.
 * Sylvest tells Hugo that he found zanium on the floor of his house. When Hugo relays this to the commander, he elaborates it into "a dust-like deposit on the floor."
 * Because the zanium is a dust-like deposit.....


 * Mestor's hair-brained scheme defies the most basic laws of physics and any kind of logic. The smaller mass of Jaconda's neighbouring planets will not cause their orbit to decay (in fact, Jupiter shares an orbit with the small trojan asteroids). Even if they did, the tiny mass of a planet would not cause a massive sun to explode.


 * Weirdly enough, throwing a big enough planet into a star actually could cause its reactions to halt and begin a nova, at least in theory. The process would likely take centuries however, far longer than what the episode implies.
 * Even if the gastropod eggs could survive a nova, it would be tens of thousands of years, at minimum, before a very tiny fraction of them would reach a planet.
 * Some species take a different perspective and play the "Long Game".

It's presumably easy to possess Azmael, with whom he has already spent a significant amount of time. There may be other consequences of possessing the Doctor which would make it less appealing of an option to Mestor.
 * Why doesn't Mestor just possess the Doctor instead of demonstrating it with Azmael?