That's serendipity at its finest as it really did look like this dude did it on purpose.
Doing that without a harness/seat belt is incredibly stupid--if he didn't do this on purpose, then he should count himself lucky as he could have easily been thrown under the truck.
I'm glad that other vehicle at the bottom of the hill saw this stupidity and stopped, or it could have had the dude's tumbling ride land on it.
BTW, does anyone have that video of a guy trying to drive up a steep hill in his Jeep Grand Cherokee (IIRC), and going too fast and flipping his SUV on its roof? That was hilarious. Tragic, but hilarious. It was posted on here a while back.