This unknown man was part of Olivia Dunham's Mind who served as a crewmen on a Zeppelin. Sometime after William Bell, Peter Bishop and Walter Bishop get in a zepplin, in Olivia's mind, he severs a main fuel line in the engine room, when Peter and Walter go to check it out he kicks a door in Peter's face and asks what Peter's name is and then fires the gun at the wall of the Zeppelin causing air to suck them in. Both Walter and him get sucked out while Peter doesn't. The man is able to pop out a parachute, and get away while Walter falls and wakes up outside Olivia's mind. After getting out of Olivia's mind and getting the real Olivia out, Peter asks Olivia who he was and Olivia responds by saying that that's the man who's going to kill her.("Lysergic Acid Diethylamide")