Bartleby Ending

Discuss the significance of the ending of the story. Why does he say "I know you" ...."and I want nothing to say to you" on p. 31? He also insists to the narrator that "[he] know[s] where [he] [is]" on p. 32. Why does he deviate from his usual response here and assert some opinion rather than being simply passive? What's the significance of his job as a dead letter handler? The nature of his death?