Ah, I saw this a while back. At first I thought that he was trying to show off or something and then got himself ran over, but after watching it a second time it appears that when he gets out of car and waves he is signaling for help!
Looks to me like he got out to show off. Then got dragged under. If he was getting out of the car for another reason (ie he needed help) he would have moved away from the car, this is possible it wasnt spinning fast.