Actually, to be serious for a moment it is not entirely impossible that there may be something to this. I remember reading an article in Nature on crowd flow some time ago. Found the link again...
Don't panic
Anyway, one of the main findings was that our intuitions about what helps a crowd move quickly may not necessarily be accurate since people don't flow like a homogenous fluid. Perhaps most relevant to aircraft evacuations is the 'faster-is-slower' phenomenon - that is the tendency for people in a rush to end up going slower.