I can really recommend Amanda Ripley's book on this subject. I personally think it gives a broader and better treatment on this subject.

One point she emphasizes: People are likely to continue their pre-disaster roles into the disaster scenario. Hotel guests continue "guest"-like behaviour, behaving nice and composed while letting the staff take care of any problems. The staff will do anything within their capabilities to take care of their guests.

People will also bring whatever they usually do into the disaster scenario. Doctors, medics and nurses will tend to the wounded. Expect rescue workers, police officers and military officers to take command, initiative and action.

One of Ripley's conclusions is particular important: Expect the majority of people to become somewhere between passive denial (this can't be happening - or if it is happening I don't want to know about it) and comatose. At the same time, we are wired for cooperation. When we're confused we want someone in control - someone who clearly knows what to do and tells us what it is. But we're dazed, and it takes some effort to get through the haze.

The logical upshot: Train staff to give clear, consise commands - and train them to SHOUT at people to get them moving when nescessary. Plane stewardesses train to shout JUMP so that people can go at a rate of 1 person per second down that slide (otherwise people will hesitate, stop to think "is this the right thing to do? Will I get hurt? What's the best way to jump?" ). You need some shouting to short circuit that kind of mental processing.

Equally important: Tell people what's going on. Don't lie to them about some minor hickups when you're preparing for what might very well be deadly disasterous.