The Moonbase - S4-E6
Revealing mistake: The doors and walls wobble badly as Jamie and Ben barricade the entrance to the medical unit.
Deliberate mistake: The shot of rocks falling in episode four is used twice - once when Unstoffe is shot, once after the captain fires the cannon.
Visible crew/equipment: Near the end of episode 3 the inspector is on the plane and just before he goes to look for Captain Blade the camera zooms out and the top of the set is visible.
Other mistake: Several shots are repeated during the implosion of the priory.
Visible crew/equipment: After Rokon's message in episode four, Eldra starts ranting and raving. A BBC camera can be seen in the doorway behind the Doctor and Sarah.
Other mistake: In episode one, when the crew wonders what The Sensorites will do to them, the camera zooms in on the Doctor as he says, "or kill us?" It then jerks with an audible click as though hitting something.
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: When the Doctor taps the ice crystals, they wobble instead of breaking.
Genesis of the Daleks - S12-E4
Continuity mistake: At the very beginning, Sarah comments to the Doctor that they haven't returned to "the beacon." When they were last on Nerva - in "The Ark in Space" - it was referred to as a space station. It doesn't become Nerva beacon until the next episode.
The Monster of Peladon - S11-E4
Revealing mistake: At the end of episode 2 / beginning of episode 3, the Doctor and Sarah are thrown into a pit. It is quite obvious that they hit a flexible mat when they land. it is gone when they stand up.
Continuity mistake: In the first minute of episode three, one of the evil robot mummies attacks Sarah Jane Smith. In doing so, it lunges forward, misses Sarah Jane, and smashes the "Marconiscope" device, which explodes in flames. However, seconds later, the 'Marconiscope' device is still visible in the next shot, but totally undamaged.
The Rescue - S2-E3
Revealing mistake: At the beginning, as the Doctor is standing in the TARDIS door, the cave wall can be seen through the TARDIS.
The Trial of a Time Lord 13-14 (aka The Ultimate Foe) - S23-E4
Factual error: The Master states that Earth and its entire constellation were moved, but constellations are merely patterns of stars (as viewed from a given point, like Earth) that may be nowhere near each other - the Earth could not really be described as being in a constellation as any sort of specific entity that could be moved.
Delta and the Bannermen - S24-E3
Revealing mistake: The bodies lying on the ground during the initial battle are rather too obviously rubber dummies rather than real people.
Delta and the Bannermen - S24-E3
Continuity mistake: The Doctor can be seen wearing glasses in some long shots of him riding a motor bike. Normally, Sylvester McCoy (who played the Doctor at this time) removed his glasses before filming. Seems as though he either forgot, or could not ride a motorbike without them.
Continuity mistake: When the Doctor shoots Stor with the De-Mat Gun, the flash starts on Stor's left-hand side, engulfs him, then jumps substantially to the right before whiting out the frame.
Continuity mistake: Throughout the serial, Bessie's tires are dry in studio shots (inside the Doctor's shed) and wet on location shots.
Castrovalva - S19-E1
Continuity mistake: The Doctor's shoes are different at the beginning of this story compared to the ones at the end of the last story.
Visible crew/equipment: In episode three, when Toos talks about the disposal of robots, a crewman can be seen behind her, toward the back of the set.
The Masque of Mandragora - S14-E1
Factual error: Giuliano makes references to the invention of the telescope. Yet the invention of the telescope was at least a century after the events in the story and Galileo's experiments more than 50 years after that.
Chosen answer: No, it was the result of the Cybermen's draining Earth of energy to their world, that also affected the Doctor, draining his energy as well, causing him to regenerate.
Also In the episode it's said that his body was wearing thin.
Dan23