Going up is fine, it's the sliding back down that'll come after that will undoubtedly hurt. Once he's on top of the rubble he pauses to grip his side, pressing down to relieve some of the ache caused by jostling himself around.

He's still absolutely freezing, but it's a good sign. He's not hallucinating either, still experiencing perfectly rational thoughts, and he doesn't want to strip the blanket and clothes off of himself in a fit of paradoxical undressing.

The apex of the crumbling debris is no place to pause. It's not a long way down, per say, but not one Crozier's looking forward to going down. He inhales sharply, steadying himself.