( Edited: see below, I stand corrected, no offence intended, AWW publishes some stats on this that I hadn’t seen. )
Yeah, white water kayaker here, I love it, but I’m not anywhere near as good or as aggressive as those guys.
There’s a film of three kayakers taking on a waterfall in Iceland where two make it, the third gets away with a shattered arm… this sort of stuff is always touch and go IMHO.