He, Jackie, and Nino Moretti had just failed at collecting money for Paulie Franchetti at a nightclub. They were driving through a tunnel going towards the Grave's-End Construction Site to kill the forman as per Paulie's contract on him, while also hoping that Paulie will take it easy on them since they at least completed one of the two jobs they had that day. While driving there they are pursued by police, which Mikey says he heard coming since he heard the sirens, but Nino replies "You hear sirens in your sleep Mikey", then Nino gives Jackie a shotgun and tells him to load it up and help them out. Jackie is loading the shotgun that Nino gave him Nino is knocked halfway out of the car by a pursuing police car and then hits his head on a parked car, killing him instantly. Jackie then goes up front and pushes Nino's body out of the car while Mikey takes out one of the pursuing police cars saying "That was for my buddy Nino."
They then drice through a the rest of the tunnel killing a bunch of workers with Mikey slowly realising that the whole situation was an ambush, possibly (and actually) set up by Paulie. Mikey is severely injured in the car crash that happens right after this realisation, the most obvious injury being his left leg, which you can see part of the bone. He gives Jackie his first guns in the game as a "birthday present" then dies shortly after, after you ask him all the questions that you can.