I'm in a DW mood again and I found myself pondering this situation again. Even though I'm in a DW head, I think I've stumbled on a more satisfying way to handle this in D&D.
The real crux of problems like this in D&D is remembering that hit points are abstract constructs that represent many facets of a character's ultimate survivability (see this post). In this sense, hit point loss is a narrativist opportunity. Well, D&D isn't a narrativist game, so hmmm.
Here's my idea (finally): In the column room example my character was a fighter (natch, I usually play fighters), with somewhere around 70 hp. The room was quite large and filled with these falling columns. I think another way to handle this would be to say "In order to cross the room, you have to make 3 successful Dex checks (or saving throws, whatever). For every one you fail you take d10 damage."
I think that makes it more narrativist. It models an escalating situation, where every column that you don't "dodge" whittles away at your chances of getting to the other side of the room alive. You're getting more tired, more tensed up. Maybe you're dodging away from one, only to step in the way of another one. In any event, if you do make it to the other side alive, the damage from the failed checks represents the physical and emotional exhaustion of such a harrowing experience.
And if the DM wanted to be extra nasty, for each failed roll impose a -1 penalty to the next roll. That would really ramp up the tension.
