Why is Felix not finished with his work, when he is driving away from the Fletcher County Correctional Institute after the play?

Felix hears Miranda’s voice saying the line from the Tempest, that “the rarer action is in virtue than in vengeance” (246) and Felix takes this to mean that he has got revenge on Tony and Sal, but that he needs to forgive himself, ultimately, for his blind faith in imagination, which created his vulnerability to Tony in the first place.