I think we've all been looking at not taking out the windshield, but the side windows. The windshield, as you say, is laminated. In order to get out through it breaking it is basically useless, any holes you punch won't expand significantly, etc... You basically have to rip it out of it's frame.
If you smash a foot-sized chunk of it near the frame while it's under that much water pressure, it should do a pretty good job of ripping loose at the edge.
If you could break the whole windshield, I'd be worried about the force of the water coming in through a hole that big. Honestly, I'd be worried about the force through side windows too, but unless you have vent or other small windows, you work with what's there.
What about the rear window? The ones I've seen broken were all tempered rather than laminated.
Ball-peen hammer, with a hole drilled in the ball and a hardened concrete nail (head ground off) epoxied in there. You'd want to make this up ahead of time
Why? I usually had a drill in the car.
Though I guess if it wasn't preassembled, just driving the nail through the window with the hammer would be quicker than trying to drill the hammer head.