Earlier in the thread (Or maybe in another thread?), someone said The Aztecs was being shown flubs and all. That sounds like they stuck in out-takes, but, I didn't notice anything different? Did I miss something, or misunderstand the earlier comment?
The way the episodes were shot back then wasn't too different from live TV, and they didn't have the luxury to go back and reshoot everything that went wrong. So there were errors that made it into the final episodes -- actors (usually Hartnell) flubbing lines, the camera shaking as it bumped into something, that sort of thing. (I noticed a bit early on where the actor playing Tlotoxl flubbed a line -- he said "No more talk against us that the gods were against us," and I assume the first "against us" wasn't supposed to be there.)
Also, the surviving film prints from which the episode was reconstructed (since the original tapes were erased) have a couple of breaks in them, so there are some little bits missing -- like a point where Ixta says the Doctor wanted to see "my [film jumps] work," where the original line must've been "my father's work."