SHYLOCKI pray you, give me leave to go from hence;I am not well; send the deed after meAnd I will sign it. (4.1.23)
Shylock has been stripped of absolutely everything, and he leaves the court to return to a life of lonely isolation. Depending on one's view of justice, and Shylock's original intentions, this is a fitting end. But if the play is about mercy, then Shylock's resolution is a note missing from the final chord. To simply cast Shylock out of the play is a dissatisfying ending for this central character.