In some disasters, a lot of people die for reasons that are later determined to be beyond their control. Yet in many disasters (sinking ships, burning buildings, weather events, etc) rescuers are surprised at how many people died because they failed to do anything to save themselves. An example is the 1994 sinking of the ferry MS Estonia, in which 852 of the 989 people aboard died, most of them because they did not leave the ship.
What happened? One person who knows the answer is John Leach, a military survival instructor who researches behaviour in extreme environments at the University of Portsmouth. He has studied the actions of survivors and victims from dozens of disasters around the world over several decades (and as it happens he was present at one of them, the fire at King’s Cross underground station on 18 November 1987 which killed 31 people). He has found that in life-threatening situations, around 75% of people are so bewildered by the situation that they are unable to think clearly or plot their escape. They become mentally paralysed. Just 15% of people on average manage to remain calm and rational enough to make decisions that could save their lives. (The remaining 10% are plain dangerous: they freak out and hinder the survival chances of everyone else.)
Of course, there is more involved, like the human tendency to downplay the actual danger in a novel situation. An article at the BBC shows us the latest research in disaster survival, based on both real events and models, and some tips on how you can survive if the occasion ever arises. -via Fark
Those who know not how to move through their fear to the other side and act always find themselves trapped in an emergency, no matter what they've been taught. It doesn't take any effort or training to realize that attempting to swim away from a sinking boat is better than staying on board.
However, for one frozen by fear, no thoughts are had, so no amount of prior training will matter.