Theory:Doctor Who television discontinuity and plot holes/Vengeance on Varos


 * The cuffs lock around the Governor's wrists at different moments in the first two votes that we see.
 * It could be that there is some hidden button or pedal that allows the Governor to signal when he is "ready" for the vote. He may have signalled at different points in time during the voting process.


 * The Doctor rigs up the laser beam in episode one, intending to kill the guards.
 * He assumed any approaching guards would see it and stop. In any case, earlier Doctors tend not to be strict pacifists, when suitably dire circumstances prevail. The Third Doctor disintegrates an Ogron in Day of the Daleks, and the First Doctor pushes an Aridian into the tentacles of a Mire Beast in The Chase to facilitate his companions' escape (to name just two incidents of Doctor-related homicide).


 * How can the TARDIS so suddenly run out of something so vital as Zeiton-7?
 * Easily. A car can run-out of petrol can't it? It's just a question of the Doctor ignoring or not noticing the warning signs, which is hardly out of the ordinary for him.
 * Remember, he does actually run out of mercury in The Wheel in Space, after earlier pretending to do so in The Daleks.


 * Why are the cannibals wearing nappies?
 * Possibly some unfortunate guard has the task of making sure they are "decent" before the cameras roll. Varos TV may tolerate any manner of marketable obscenity, but the naughty bits of drooling deranged maniacs do not necessarily inhabit that category...
 * Just because they're cannibals doesn't mean they want to go around with their junk dangling about all over the place. For one thing, having some kind of protective covering down there keeps a fairly important, sensitive and easily-attacked or damaged part of the anatomy protected from enemies or the elements. Numerous supposedly "savage" cultures from all across history have tended to devise some kind of covering to protect the external reproductive organs, so it's not a huge leap that the savage outcasts in the Punishment Dome might also think to do the same.


 * Both the desert and the water are illusions, but the desert parches whereas the water doesn't quench.
 * What water? The only water in the illusion is in the glass Peri is holding, and he never gets near that. Besides the 'parching' of the desert is probably aided by actually heating the corridor he's in.


 * The spaces between the planks/bars in some of the doors of the punishment dome are big enough to squeeze through.
 * They're also under constant video surveillance in what amounts to a massive death-trap, so the advantages of being able to escape from a cell somewhat easier tend to be nullified. This may also be part of the entertainment; watching to see if the prisoners can escape.
 * This is also arguably more of a production error/limitation than a plot-hole, strictly speaking; presumably it wasn't possible or practical to make the cell doors more realistically impenetrable without sacrificing either budget or ability to film what was happening clearly.


 * Why would the GMC invasion force from Sil's home planet turn-back at the end of the story just because they've discovered an alternative source of Zeiton-7? Since they are already on their way to take control of the planet, why not simply go ahead and then they wouldn't have to agree to pay whatever the Varosians wanted for it? The discovery should spur them on, not draw them off!
 * The resolution is vague, but the announcement that new reserves of Zeiton-7 have been discovered does not specify who has discovered them. If they have been discovered by a business rival of Galatron or an enemy of the Mentors, then securing the Varosian supply as quickly as possible, without over-taxing their military forces, might be the most expedient option.


 * What part of the 'vengeance' mentioned in the title comes into the serial?
 * It's not elaborated upon very clearly in the broadcast version, but the entire political system of Varos is, according to backstory, basically an act of vengeance. Essentially, it used to be a prison colony, but then the prisoners rose up against the oppressive guards, and created the system of government wherein all votes are put to the people, but if the people disapprove of the Governor's decisions then a "No" vote results in the Governor's death. Essentially, the prisoners of Varos are taking their "vengeance" upon the Governor. The novelisation explains it in a bit more detail.


 * It seems a bit remiss of the Time Lords to make their primary mode of transportation reliant on a mineral only found on another planet for its locomotion. Surely they could at least create a device to generate Zeiton-7 on Gallifrey itself?
 * They presumably don't have a choice; if you live in a country with no natural oil reserves or production, then if you want to fill your car with petrol you're kind of reliant on buying it off a country that does. Same principle, just on a galactic scale; presumably zeiton-7 (like most substances, to be fair) is both the easiest or only method of powering the particular time-travel function that it does and cannot just be magically produced out of thin air (since if it could, well, it wouldn't be rare).
 * Also, the ending reveals that Varos apparently isn't the only place where zeiton can be found; it's presumably just the only place the Doctor can call to mind. Him having gaps in his knowledge is not unprecedented. Alternatively, he may also have been saying "only" because Varos was the only source of zeiton near enough for the TARDIS to reach without completely running out of fuel, but simply didn't feel like making the distinction to Peri.
 * It may also indeed be available in plentiful supply on Gallifrey -- but considering every time he goes back there they try to kill or imprison him, the Doctor may simply be reluctant to go back to Gallifrey if he can possibly help it, even in dire circumstances, so doesn't even bring it up as an option.