This Wired magazine article summarizes a part of the NIST report on the World Trade Center disaster. Basically, those who obeyed authorities’ instructions to stay put and await rescue, and who also obeyed their training to use the stairs, were more likely to die.
Fortunately, this advice was mostly ignored. According to the engineers, use of elevators in the early phase of the evacuation, along with the decision to not stay put, saved roughly 2,500 lives. This disobedience had nothing to do with panic. The report documents how evacuees stopped to help the injured and assist the mobility-impaired, even to give emotional comfort. Not panic but what disaster experts call reasoned flight ruled the day.