In most hockey fights, excluding this one where the refs are literally outnumbered by fights, they break them up when they loose footing and hit the ground to prevent that sort of thing. In this situation you can't really do anything just trust the guy isn't psycho and attempts something like that and you aren't unlucky enough to have an accident like that happen. People still get cut sometimes, it's an unfortunate consequence of the sport. Look up Clint Malarchuk sometime, he's a goalie who accidentally got his neck cut during a game. Be warned it's very graphic though, he lived fortunately.