you know the jam in the aisles when a plane lands and everyone stands up to get their bags and wait for the doors to open...
Okay, imagine the same jam when everyone is panicking, trying to put on a parachute (which they wouldn't know how because nobody ever watches the safety videos) and then climb all over each other to get to the doors first...
Sounds like a recipe for chaos to me, in which no lives would be saved at all, even if there was time to do it properly. And as mushroom says, most crashes happen too quickly.