I have worked for over 10 years in crowd management.
Years ago many people died in a ballroom in Belgium. Fire had broken out and people finally tried to leave the way they came in, many did not make it.
What a shame, the ballroom was on the ground floor and there were many windows....
There are countless stories like that. People have a false sense of security in a plane or in an arena and so drop their guard. When the
hits the fan it's too late, they'll head for the door they came in through.
Only pointing out the other exits helps.