Well, getting video's up here soon. But here's a brief description. In the hangar of Vacant, there is that small wooden room, walk into it, jump onto the bench then crouch jump onto the fridge, then crouch jump to the center ceiling of the hanger, and you should land on like, a tiny piece of wood, walk down it, take that first walkway left, and jump out onto the tops of the hangar, my crew and I had fun trying to servive with minimal health, and no regain.
Good luck.