Revealing mistake: The knife that Leela kills Meeker with is very obviously loosely attached to his clothes. It wobbles back and forth after he falls.
Revealing mistake: In episode 3, the section of wall K-9 knocks down is obviously precut, complete with debris on the floor.
Revealing mistake: When K-9 shoots one of the infected men, the blast beam appears to come out of his eyes, then moves down to his snout as the camera moves.
Answer: It was never destroyed on-screen; it was intact at the end of the TV movie, and destroyed by the start of the 2005 series. It was destroyed in the novel "The Ancestor Cell," but in a completely different manner to what happened in the series.
DaveJB