Had I been a passenger on either of these flights and aware that there was some sort of potential bomb threat, I would not have sat calmly in my seat waiting to either blow up or for someone to get around to bringing stairs to the plane.
I would have evacuated myself, via the slide if necessary, and I am sure that other passengers would have joined me. Who would have stopped me?
I am amazed that passengers didn't take things into their own hands. Either they didn't have any idea whatsoever why they had quickly landed at Prestwick (I find this hard to believe) or something was said to them to keep them quietly in their seats, but what?