I can't stress enough - IMPACT TOOLS WON'T WORK ON FRONT AND REAR WINDOWS - and in some cars, they won't work on side windows. Follow the bubbles and try to open the door. You may need to wait for the water to rise before you can open the door. If you blow out a window while under waters, several tons of water are going to slam into you at once.
It's a low rate of survival situation, in all cases.
I forgot about that. My wife's car one of the selling points was safety grass in the side windows (as well as the front).
However I thought that back windows were not, both from having my own shot out with a pellet gun and that mythbusters episode where they tried to put pressure on the back window while shooting it with a pellet gun.
Even if you manage to survive the impact with the water but hitting at a low enough speed to not pop the air bags or bend the center of the car then you still have to be alert enough to either cut or unlatch the seatbelt, wait and unlock the doors then open them. A lot of room for error when stressed.