[m463]

I wonder if we couldn't have the equivalent of the water barrels near the start of guard rails, but for crowds?

Maybe giant inflated or crushable areas around an exit that could take up slack?

maybe tie the crush event with something else, like opening extra doors, turning on lighted warning signs or illuminating exits?

[lifeformed]

Doors with crash bars are kind of that. If there's too many people, they'll push up against them and force them open.