Revealing mistake: Whenever the TARDIS's scanner picture of the Doctor's laboratory is shown, the TARDIS itself is always in the picture.
Audio problem: About 10 minutes into episode 1, the sound of a pencil being dropped and rolling across the studio floor can be heard. (00:10:00 - 00:11:00)
Continuity mistake: At the end of episode one, when the Doctor and Taron spray paint onto the invisible Dalek, they use two different colors. At the start of episode two, the Dalek is suddenly black and painted on all sides.
Visible crew/equipment: In episode four, the Dalek chasing the heroes up the ventilator shaft is supported by strings.
Visible crew/equipment: After the Doctor recovers from his coma, he gets up and stands at the console. A reflection of a crew member can be seen in the shiny part of the central column.
Visible crew/equipment: As The Daleks plan to release bacteria into the atmosphere, a crew member is reflected in the glass box containing the bacteria.
Revealing mistake: Jo is hit by a rather large rock. Katy Manning visibly winces before it strikes (and bounces off lightly).
Audio problem: In the first scene with the Dalek Supreme, the lights on its dome are way out of synch with its speech.
Visible crew/equipment: At various points in the story, the pots for the plants of the Spiridon jungle are visible. Episode two has a couple of noticeable moments, when Codal is captured and when the Doctor is led away by The Daleks.
Continuity mistake: When Wester - an invisible Spiridon - is treating Jo's arm, his shadow can be seen.
Continuity mistake: In episode five, Jo's hairstyle changes. She has one hairstyle in the bulk of the episode, which was filmed in the studio. And a different one during the "Plain of Stones" scenes, which were shot on location.
Revealing mistake: In episode 5, Codal discovers that what he thought was Taron is an invisible Spiridon. However, there is a glimpse of the actor inside the fur costume as he attacks Codal.
Visible crew/equipment: In episode five, when Taron knocks out the Spiridon, you can see a BBC camera in the foliage behind him.
Continuity mistake: In the very first scene of the story, Jo is holding a gun as she opens the TARDIS doors, but when they come into the console room, she has no gun and is using both hands to support the Doctor.
Plot hole: 10,000 Daleks sounds impressive but it wouldn't be enough to invade a planet, let alone an entire galaxy.
Other mistake: The end titles of episodes 2, 5, and 6 of "The Green Death" were run backwards and upside-down. According to some published accounts, this was due to the telecine operator forgetting to rewind the end title film sequence before playback.
Plot hole: Professor Jones says they tried to borrow the cutting equipment a few weeks ago, but Mr. Stevens says it was yesterday. One of them must be wrong...
Revealing mistake: When Benton jumps over the maggots to get into the cave the Professor and Jo are hiding in, the jump causes the floor to move, giving away the fact that the floor is wood covered by a small amount of gravel.
Plot hole: Jo should know what the dematerialisation circuit looks like. She saw it in 'Terror of the Autons', 'The Three Doctors' and several other episodes.
Revealing mistake: In the finale, when Stevens is beating on the computer console, it moves around quite a bit, even thought it is supposed to be a strong and stationary object.
Answer: TARDISes are generally available for properly authorised use on Gallifrey; they're not usually assigned to a particular Timelord on a long-term basis. The Doctor stole his when he left his homeworld.
Tailkinker ★