For the past couple of days, I've been trying to practice Corpseflesh's rooftop skip for the Marine mission Refinery. For it to work, you need to hit it at a specific angle. The best way I've found to go about it is that you want to be just to the left of the gap in the barbed wire. As you're walking up it, you need to swing left, then come back in towards the right a bit. After you turn back right, you need to jump. If you angle yourself a little too far to the left or right when you jump, you will hit the death barrier and die instantly. It's tricky to do, but if you get decent at it, I think it could become pretty consistent. I'm going to include a video to show it off, so if anyone wants to try it, they can use it as a reference.