I have the bailout diagrams of the B-17. It had 4 emergency exits. The exit order on exits handling 3 men was in the order of their distance from that exit, or degree of difficulty of exit .
For instance, for the two waist gunners and belly turret, it was left waist, right waist, belly gunner last because he had to park the turret in a particular position to get out of it, and most men couldn't fit in that turret wearing their chute so his exit takes more time.
The pilots, upper turret gunner, and radioman exited the bomb bay, a big exit, because it's got the radioman and upper turret gunner exiting both first, then the copilot, then pilot last.
Under better conditions the pilot gave the bailout order, but with a aircraft falling out of the sky, maybe coming apart, i'm sure most men didn't need that order they got to a hole, and if no one was in the way, they jumped.