![Futurama mistake picture](/images/screenshots/209000-209999/209416_sm.jpg)
Continuity mistake: When Fry, Leela, and Bender make it back to the ship, Fry's hair is messed up. When the bee is unfolding itself, Fry shouts "Look out!" and his hair isn't messed up. Then when he says the bee will have to go through him, his hair is messed up again.
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]