The first half of this episode where Bear shows you what to do if your car goes into a river or lake was pretty interesting. And it's cool because they actually put Bear in the car and he gets submerged under water. It isn't staged, he's actually doing it!
So basically your best bet to escape the car is to get out simply by opening the door BEFORE the car is completely submerged in the water. Bear says on average you have about 2 minutes before this happens (I'm assuming this is with the car windows up, because that is how his car was). If for some reason you can't get out before the 2 minutes, then you have a very limited amount of time because you won't be able to hold your breathe under water too long of course. In this case, you should keep your seatbelt on, then break out the drivers side car window with something sharp - Bear used the headrest from the drivers seat (the sharp pointed end). After you break the window, remain in your seat with the seatbelt on until the car fills with water. If you don't, he says the strong current of water coming into the car will often times knock someone unconscious and you will drown. After the car fills with water, release the seatbelt and you should now be able to open the car door, due to the pressure being released.
He didn't cover in the scenario that if you happen to drive with your window down, which I do most of the time, you probably wouldn't have to worry about breaking out the window. Simply open the door and escape!
The 2nd half of the episode talked about how to survive a rattlesnake bite. Basically don't do anything to the wound area, keep the bite low to the ground. Most people get bit on the leg or arm, so simply keep that limb on the ground and call 911 with your cell phone.