Originally Posted by
ByrdluvsAWACO
People, I really don't see the confusion here. The door acts as a plug in the airframe when the cabin is pressurized, and because it has to move inwards first it is impossible for someone to open the door.
It is NOT impossible! A physicist with a bit of time to spare could calculate the force created on the door flying a 30000 feet, but it is not that great and the levered door handle provides enough force to break the seal in any case. One the pressure has equalised the door can be moved freely.