I hate to ask this but...

[PvtLastClass]

It was a little frustrating to me to see that someone SPEEDRUNNING that sequence was only barely able to make it through. I kinda thought puzzles generally gave you some time to understand what's happening and think. Often what Valve does, is if there's going to be combat, running, or anything fast-paced, they take it in two steps. First, you walk through the area once to find some switch or something, letting you get the lay of the land. Then, the switch makes you go someplace else and triggers combat. From there, you have a better idea of where to go and what to do.