This is a kind of cheat by taking advantage of yet another hilarious glitch. What you do is go on a Death Run and drive straight to Gasworks. Park the car just outside the entrance where the flame-barrier is, wait for the timer to get a second or two away from zero, and aim your shotgun at the ground. The timer runs out which activates an ejector seat that springs you up above the camp and right where the Top Dog (boss) is hanging out. He only appears if you use the ladder, though.