The intent of the evacuation manager is to maintain an orderly evacuation, not to kill a few people. It's a big difference from a moral standpoint, but the result is the same.

Here's the prisoner's dilemma. By having an orderly evacuation, a healthy athlete in a delayed group may die, when he could have survived if he had ran out sooner while running over people. However, if everybody decides to run over people, then everybody is in more danger. In that case, the strongest and luckiest people survive first. All or most people must cooperate in order for the evacuation to be orderly and safe for the common good. Unfortunately, there is some chance the people who feel strong or lucky will not cooperate.