Wired News has a short essay about how people saved their lives on 9/11 by ignoring authority. They survived by discarding the safety advice and training they’d been given and acting on their own initiative. I’m not surprised. People really aren’t stupid, and I don’t think people in emergency situations panic nearly as often as we’ve been led to expect. And, as they point out, the people in the buildings with cell phones were better informed than the dispatchers in the 911 call centers.
One example the article gives is using elevators vs. stairs to evacuate the towers. The usual advice is to take the stairs, and for able individuals in smaller structures this probably is a reasonable precaution. But for the WTC buildings this advice didn’t make much sense. There were too many floors, too many injured people, and too much smoke and confusion. Some people who were on elevators at the time of the attacks undoubtedly died, but the working elevators kept working long enough that many people were able to use them to get out quickly. While hundreds of others who did as they were told were stuck in stairwells when the buildings collapsed.
I’ve seen a lot of buildings with signs that warn that "Elevators will automatically be disabled in the event of a fire". I think that’s a serious mistake. If an elevator is damaged badly enough to be riskier than the fire then it should shut itself down, but shutting down all elevators everywhere in the building whenever a fire alarm sounds seems more like legalistic CYA than an intelligent evacuation plan. Is it risky to use an elevator to evacuate a burning building? Probably. But being in a burning building is already pretty risky, and the person best able to evaluate the sitation is the person who’s there.