What causes this sound?

Serious replies only, please.

I'll do my best to explain it, but I'm morbidly curious why in this particular clip from one of my favorite shows (Impact: Stories of Survival / Did You See That), the man made this... really disturbing and saddening "hnnnngh...hnnnngh...hnnnnnngh" noise after he slammed into the ground from a faulty parachute or something to that effect. It was deep and gutteral. I thought it might be explained by an obvious brain trauma injury upon crashing, but I wanted to hear what others think.