Theory:Doctor Who television discontinuity and plot holes/Survival


 * After twenty-six years of references to the TARDIS lock as having elaborate electronic security systems requiring specific motions, specific DNA, and / or cipher indent keys in order to open it, the Master seems to be pushing the boundaries of optimism and plausibility when he tries to pick the lock with a letter opener (Episode 3).
 * The Daleks were able to open the T.A.R.D.I.S and they werent 100% experts like the Master so the thing that the Master tried to open the T.A.R.D.I.S with a knife isnt impossible. Also he could have learnt some new tricks.
 * Sonic letter opener?
 * For all the fine talk about elaborate security systems, DNA locks, cipher idents and the like, we should remember that for large parts of the series the TARDIS can be opened with what appears to be a simple cylinder lock key. This suggests one of two possibilities: 1. the TARDIS key merely looks like a cylinder key, but is in fact far more complicated and not quite what it seems on the surface, meaning that the principle can be extended to suggest that the Master's lockpick is in fact not just a letter opener but is in fact also more complex than it seems. Or 2. the Doctor is bluffing with all that talk about the TARDIS's elaborate security systems and it is, in fact, possible to jimmy open the TARDIS lock with a letter opener. Whichever one is the truth is open to the individual viewer but, let's be honest, it's not like either is impossible given what we know of both the Doctor and the TARDIS.


 * Why doesn't the Master, as much a Cheetah Person as Ace was, just teleport off the planet?
 * The Master doesn't realise that to use the teleportation powers does not necessarily mean becoming a full Cheetah Person.
 * It is equally possible that the Master has never had a place that he truly considers home.
 * Further to this point, since the closest thing he has to a true home is Gallifrey, where his life is almost certainly forfeit (after the treasonous incidents of his last two visits), he may have deemed it marginally safer to remain on the Cheetah world until he could effect a less suicidal escape route.
 * In fact, the Bible and other background material written for the TV movie and (hoped-for) new series explained that the Master, at the last second, teleported home into the waiting arms of the Castellan on Gallifrey. And he knew that's what would happen, which is why he didn't try it until the last second. Of course none of that was ever referenced on screen, so it's not the canonical explanation. But certainly it shows that an explanation isn't hard to come by.
 * Not to mention the risk that the Doctor makes clear: that using the teleportation ability can push the mutation past the point of no return. Not a risk that the Master would take lightly, and certainly not with a steady supply of expendable humans who could potentially take that bullet for him...