Corrected entry: When Costigan is exiting the lift with Sullivan he is shot, but how did the man who shot him know he was there? Costigan only told his friend from the police academy, and Sullivan obviously didn't know the killer since he was suprised to see him and knew nothing about any other moles in the police force. This isn't to be confused with Mark Wahlberg's character shooting Sullivan at the end of the film.
Nick Bylsma
21st May 2007
Correction: The man who shot him was also a mole in the force. That's why he said "We gotta stick together".
Nick Bylsma