> I mean, think of all the wasted space and weight having 8 exit doors on a airplane; they don't crash often And if we had all doors except one passenger seat,

> I mean, think of all the wasted space and weight having 8 exit doors on a airplane; they don't crash often And if we had all doors except one passenger seat, it might be even safer. We neither optimize for absolute highest survival rate nor for absolute highest convenience/efficiency. The question is-- how much does the second staircase improve survival? Is it the most economic way to get that survival difference?