Next time somebody rolls one, notice how the top of the doors are usually bent outwards, the roof acts like kind of a wedge between the doors forcing the top of the doors out. Simple physics, the force to bend the door tops out, without the doors, is likely to be straight down. Not all of the problem, just another piece in the puzzle. I've done a significant amount of body work in my life. I was taught the best way to get the dents out is reconstruct in your mind how it was dented and reverse the process to remove the dents, you get pretty good after awhile in reconstructing in your mind how it was crushed and in what directions.
You believe what you want to, I didn't live to be this old by being foolish. I plan for the worse and hope for the best.
I watched my brother barrel roll one maybe 8-10 rolls down the side of a hill. The door popped after maybe the sixth roll, the seat belt stud pulled out of the floor, he was ejected downhill and the roof rolled right over him. The roof on the side with the opened door was significantly flatter than the passengers side. My wife low speed rolled one. The roof was pretty darned flat. But there was room for her head because of the B pillar. The top of both doors looked kind of like floppy dog ears, they were both bent outwards. the door latches were still latched. My Dad always told me to learn from other peoples mistakes, it is often the less painful way to learn.
The doors aren't likely an integral part of the roof support, but IMHO the roof (area) is likely to have less support and be weaker in a rollover without them, not to mention total body integrity..
