A similar situation happened during jump practice for our regional championships last year. A good friend of mine, who is a very accomplished jumper, was taking some practice single cuts, as he usually 3/4s and double cuts. He took a nasty OTF crash and was knocked out, luckily there was enough people in the boat to jump in the water and around to get the backboard, and bring him safely to shore. He turned out okay and was skiing again a week or so later.
This experience gave me a lot of knowledge: To always be prepared, and a better idea of knowing what to do in a situation like this. AND to know that it can happen anytime, in practice, as it did here, or during the tournament. Safety is PRIORITY.