It is where he feels close to his limit. It's all about perspective. Risk, danger and the ever-present fear are possibly the allure. And if we die, we die doing what we like, which is to be on the edge of living. But I accept this risk with joy in my heart for, because of the risk, I live.
People talk about 'conquering' a mountain, or 'beating' a steep slope - that's exactly wrong.
It's not aggression or warfare. To do these things, you have to force yourself into a kind of passive state, where you blend in as part of the mountain, part of the snow, part of the skiis, part of the environment. It is totally symbiotic. I guess extreme skiing is really all about going where you thought you couldn't.