Jump off the bridge. Play until you reach the room with the Radar Tracker. Take it, and try to leave the room using the door you entered. Nicholai will call you. After killing him, Carlos will enter. After talking with him, leave the room (do not use the hatch to the Rail Cannon). Turn around and get in the radar device room again. Carlos and Jill will listen to a radio call from Barry and the game will continue with the final scenes.