Chidi: You cannot kill Janet. Killing is one of the most famous moral no-nos.
Eleanor: Janet is a nonhuman object who was sent here to help us, and the way she can help us is if we kill her. We're doing one small murder-y thing for a bigger, better reason. The ends justify the means.
Chidi: Do you know who said that?
Eleanor: Was it someone nice and great, like Oprah?
Chidi: It was Machiavelli... A very non-Oprah-like figure. And what happens after we kill her? We'll have to lie to everyone about what we did, and lying is always wrong.