Continuity mistake: After Leela wipes the egg off her face, her cloth and cup are in front of her on the table. After Fry gives his little speech, they have disappeared.
Continuity mistake: When Fry has a bite of his pizza slice, the pizza slice change size between the shots. (00:20:30)
Continuity mistake: When Fry starts watching one of his old videos, all the objects that were on the floor in the previous shot disappear. (00:10:55)
Continuity mistake: At Fry's celebratory party, he and Bender are smoking cigars. Fry's cigar is smoking, but Bender's is not. (00:06:30)
Continuity mistake: When we first see the team sitting round the table, Bender is sitting next to Leela. As the egg is burst with the syringe, we should see Bender in shot, but he isn't there. (00:01:45)
Continuity mistake: When Bender's cans first fall onto the floor, they don't have labels on them, but in the next shot they do. (00:05:00)
Continuity mistake: When Bender's cans first drop out of his jacket onto the floor, the number of extra items on the floor increases when the security cameras are looking down on him. (00:04:55)
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]