Continuity mistake: During the court case, the lady judge has a band-aid on her forehead. It disappears and reappears throughout the scene. (00:06:20)
Continuity mistake: At the end when Bender and Fry are polishing the ship the foam on the ship differ, disappear and reappear between the shots. (00:20:35)
Continuity mistake: After Brannigan has explained the plan to attack the Neutral Planet, Fry turns around in his chair and you can see the head rest goes together with the chair. When it cuts the head rest sits on a bar attached to the chair. (00:16:35)
Continuity mistake: When the professor is talking to Zap and Kiff when they are sitting at the table Hermes has two buttons but later he only has one button.
Continuity mistake: When Bender and Fry are loading the dark matter into the left engine the amount of matter on the trolley differ between the shots. (00:19:25)
Continuity mistake: At the end when Bender and Fry are polishing the ship, Bender change from polishing the side of the ship and the window between the shots. (00:20:35)
Continuity mistake: When Brannigan and Kif leaves the DOOP Headquarters the broken glass on the main entrance door differ between the shots. (00:08:05)
Continuity mistake: When Fry and Bender are playing the chess looking game the horse lays its head on a red square. When it cuts its head is on a white square. (00:00:10)
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]