Continuity mistake: When the crew and Bender are sitting on the couch, Bender says, " Oh, oh, oh! get ready for this part!" Note the vent behind him is missing the three lights that have always been on it. (00:13:25)
Continuity mistake: Bender is shown to be wearing clogs in the scene where he arrives back from Holland after saving a turtle. However, a few seconds later when he's knocked over, the clogs are gone.
Answer: You are thinking about episode 20 of series 2 - "Anthology of Interest I". She technically never kills anyone, but in the episode she ask a "What if machine" (one of the Professor's inventions) what would happen if she was more impulsive. The machine then shows the more impulsive Leela killing off the Professor to get the money from his will and thereafter killing Hermes, Bender, Scruffy, Cubert, Nibler, Amy and Zoidberg to cover it up. Finally she does something really impulsive with Fry.
Andreas[DK]