If you tried to open the door, it would indeed be
impossible to open it.
Depending how deep you were, there would be (many lbs/sq in)*(door
surface area).
however, that is the wrong solution.
Roll down the window. then go out.
Cars where the windows can be rolled down are getting harder to find.
My vans (both of them) have those stupid power windows that won't operate
unless the car is running. Oh, and the back windows don't open at all
(well, OK, they open a couple of inches for ventilation).
So you could easily put 8 or so people in there, who wouldn't be able to
open the doors.
My sedan still has the roll-down windows. (But then, *I* bought that, where
my wife picked out the vans.) I hear that immediately after I bought mine,
power windows became "standard", though.
Vince