Had a friend doing an exhaust hanger on his 92 olds tornado. On stands just tall enough to get under the car, for some reason he went in on his chest then tried to roll to his back. He managed to wedge his right arm across his neck so he couldnt breathe or holler and couldn't roll back to unstick himself. He's lucky a couple of us were there just havin a few beers and saw him kicking like a mouse in a trap. I asked him what the hell he was doing, and after a few moments of no answer i got down to see what was happening. Had to jack the car up off of the stands and help twist him out from under the car. Yeah i TRY to not work alone on cars after that experience.