The Evil of the Daleks - S4-E9
Trivia: The Doctor only appears in pre-filmed insert scenes for the fourth episode, as Patrick Troughton was taking a holiday during production.
Trivia: In the animated version of this story, when we're at the police station, there are some wanted posters on the wall in the background. One of the wanted posters is for the original Master, Roger Delgado.
Visible crew/equipment: (Ep. 2) When The Doctor, Jo, and Dr. Tyler are taken into Omega's palace, in the first shot of the multiple passageways (right before Jo says that it looks like Aladdin's cave) the curved chalk actor's mark is visible on the floor, then we see it again in three following shots. Note that when they're all escorted further inside, just as Dr. Tyler comments about the matter/anti-matter not making sense, Jon Pertwee looks down, presumably to make sure he hits his mark.
Castrovalva - S19-E1
The Doctor: That's the trouble with regeneration, you never quite know what you're going to get. (00:12:15)
Earthshock - S19-E6
Question: In Earthshock, season 19, at the end of episode 3, the Cyber Leader views his troops marching down the corridor. Each column is headed by a Cyber Leader. Is this a mistake, or is there more than one Cyber Leader allowed per army?
Answer: In 'The Five Doctors', three separate Cyberleaders are definitely used. So it's likely that Cyberleaders are like unit commanders, of which a fair-sized army might have several.
Daria Sigma