Holy... He's so lucky that he his body turned to go down feet first with his skis still locked in. Those two rocks towards the end would have killed him easy. His skis looked like it caused him to jump over the rocks.
I don't understand what happened there though. Did he intentionally go backwards after stepping in? He didn't seem like he was panicking at all while starting to slide backwards. Plus he looked like he was firmly planted with his poles while stepping in. Still, I would feel too sketchy stepping in where he did.
This is where snowboarders have a major advantage I'd say. We would have to sit down to strap in there. Standing up is a different matter though