Earthshock - S19-E6
Plot hole: The Cyber Leader states that he needs the Doctor to pilot the TARDIS. It makes no sense then, that he would try to kill the Doctor once inside, and before the TARDIS had landed in a safe place. (01:33:55)
Earthshock - S19-E6
Revealing mistake: When the Cybermen break through to the bridge, they brush against the door and it bends as if made of cardboard. It was supposed to be made of reinforced steel. (01:09:10)
Earthshock - S19-E6
Audio problem: In episode two, the Cyberleader misses a button on his console, yet we still hear a beep...
Earthshock - S19-E6
Visible crew/equipment: As Lieutenant Scott is moving up the scaffold staircase, you can see someone at the top of the screen reading a script. (01:04:20)
Earthshock - S19-E6
Continuity mistake: The hole that the Cybermen make in the door increases in size just before they step through it. (01:09:10)
Earthshock - S19-E6
Factual error: As the spaceship approaches the Earth of 65 million years ago, the Earth looks very much like the present day one. Hasn't anyone heard of "continental drift"? The Earth's land masses of 65 million years ago were not where they are now. (This has been fixed on the DVD)
Earthshock - S19-E6
Continuity mistake: In episode four, as they approach the TARDIS, the female member of the remaining troopers is grabbed and doesn't make it inside. But when the troopers do get inside the TARDIS, it's a man that's missing.
Earthshock - S19-E6
Other mistake: In episode 4, as the Doctor, Tegan and Nyssa are being led away from the bridge, the Cyberleader loses his footing when he gets to the bottom step, and stumbles/trips up (He recovers himself very quickly; so quickly in fact, that this mistake was left in the finished episode). (01:24:45)
Earthshock - S19-E6
Plot hole: The freighter traveling back in time makes no sense. According to Adric, the Cybermen's computer is responsible, yet the Cybermen possess no such technology; their machine's task was simply to navigate the freighter towards Earth. The idea that time travel could happen by accident is also absurd. (01:30:05)
Earthshock - S19-E6
Factual error: The Cybermen sets four explosive charges around the outside of the door, yet only the middle part of the door is damaged...
Earthshock - S19-E6
Continuity mistake: The mouth panel of the Cybermen costumes was originally intended to be a clear perspex panel. During filming, it was felt that this showed too much of the actor inside the Cyberman costumes. So a decision was taking - mid way though filming - to paint over the 'clear' panel with silver paint. However, this does result in the mouth panels of every Cyberman alternating from 'clear' to 'silver' from shot to shot.
Earthshock - S19-E6
Revealing mistake: During the "cliffhanger ending" at the end of episode 3, it's blatantly obvious that the three columns of advancing Cybermen are merely mirror images of each other. The head of each column has black head bars indicating leadership, and is holding his gun in exactly the same position.
Earthshock - S19-E6
Revealing mistake: When Lieutenant Scott kills the second Cyberman on the bridge, he starts falling down way too early.
Earthshock - S19-E6
Revealing mistake: The "dead" crewmembers at the end of episode two can be seen breathing.
Earthshock - S19-E6
Visible crew/equipment: Just after the Doctor has explained the anti-matter to Adric, the shadow of the boom mike is visible in his blonde hair.
Earthshock - S19-E6
Revealing mistake: Just before the Cyberman fires on the console, you can see Adric trying to keep as far away from it as possible before it explodes. (01:35:05)
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