I honestly don't think he tried to reverse, he obviously stalled it as we know, and being a manual, attempting to re start the engine, had a slight relax on the brake pedal, a few inches roll back, simply threw the car off balance into a potential roll, the "only" chance he had to save it is to do what he did, and reverse (well roll backwards), unfortunately he didn't win this one, the only thing he did wrong was not stay hard on the brake until it started, but in that situation, he would not have known just how critical NOT rolling back even a few inches would become.
Easy could have killed someone, but they obviously had seatbelts on, and were not being stupid, just one of those things, at least its on video , a small consolation to the cost and work ahead to get back out on the tracks again, now he has a excuse to buy a auto GU and kiss such stalling problems behind
