anengineer is totally correct. The "System" and by that I mean regulators, operators and manufacturers, has to spend more time considering events surrounding evacuations. It is clear that as flight crew we have very little time to acquire sufficient information to justify an evacuation yet with a possible fire, we may feel we have to react without out it. Until we are given more guidance we will have more (just like in the sim.) Smoke-Stop-Evacuate situations. I think we should spend more to see if what we do now is really a sensible way of doing things.
Then we must seriously look at passenger briefings and passenger behavior - under stress. I believe most airline passenger briefings are a complete waste of everybody's time and effort. Nobody listens for a start and secondly, the briefings lack presence and honesty. Maybe we should consider "bite sized" briefings just before the event? Do passengers really need a seat belt briefing? Is the oxygen mask briefing correct? And so on...
Then we have to consider passenger actions when it all goes wrong. What is clear is that when it does wrong, the average cabin is split into about three camps. Those who are going to live, those who'll probably die and those in the middle. Like for example, the passengers in the hijacked Ethiopian 767 who inflated their life jackets before the aircraft ditched. Here, if we are to believe a lady who found herself on the wing of the Glasgow 737, she considered that there was no way down because there was no slide. But what did the safety card show show, the one which she was asked to read before departure? Also, she went to say that two girls jumped down without injury. But she's on an aircraft wing after having be told to evacuate - just what do have to do to make this lady jump? Unless planning takes into account (or totally ignores) the "lady on the SPT onimbus," we'll not have a worthy evacuation system. I say worthy because we have to have a system that is built for the majority of passengers - because if we build a system robust enough to protect the dumbest and least able we won't be able to go flying. And this is where we must be honest. And finally, we must be totally clear that not every person will be able to evacuate an aircraft a certain amount of time, which may have consequences!
In passing, we should also consider that we will have what might be described as "useful" people in the cabin as well. The guys who were helping fellow passengers to clear the bottom of the slides in Glasgow were doing remarkable job. Considering a total lack of briefing (which takes to the above) and preparation and the fact that they believe they were close to a burning aircraft, they did an excellent job.
Which leads us on to our last line of defence - Cabin Crew. It sounds like this crew did a good job. They shouted at the passengers to get out and carried on doing so until they did. It looks like all the doors were opened and all the slides we deployed. They should be congratulated.
Finally lawyers - what do we have to do before this corrosive scum damage our lives more than they are already doing?