When it reaches the ground floor, Costigan is shot in the head by Officer Barrigan (Dale), who then shoots Brown and reveals to Sullivan that Costello had more than one mole in the police.
Costigan is shot in the head by Officer Barrigan (Dale). It reaches the ground floor. Officer Barrigan (Dale) then shoots Brown. Costello had more than one mole in the police. This is what Officer Barrigan (Dale) reveals to Sullivan.