You're a psychopath undercover as a cop you've gone unsuspected for a while and you were pretty confident that no one knew... but Doakes was onto you, he knew something was up

You guys are working on a case and split up except you go to the harbor because you ordered some furniture from Taiwan and was hoping to kill the people that shipped the furniture while you were looking around you saw Doakes

"Surprise motherfucker." He said in an aggressive tone "Why the hell are you here?"