Continuity mistake: When Leela revives Fry at the end, she is right next to him. When Fry regains consciousness, Leela is at least a half foot away from him without enough time to move.
Continuity mistake: When Fry and the kid are racing along the motorway, just after they let go of the cars they are holding onto, they head into a lamp post. This leads them to banging their heads and collapsing on the floor, because the ribbon they were holding onto forces them into the lamp post. When they fall on the floor, the dust shoots up. After the dust disappears, the lamp post has as well, meaning that the ribbon isn't actually tied around anything.
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]