So what happens when the battery dies with you in the car? Or if you fall in the river, would you still be able to open the door?

 

Well it would be smart to have a manual release where you could slide it down yourself. Under water, it might even be easier to slide it down versus opening a car door under water pressure...

 

Yes, that's a good point.

 

well, because complete side of the car is completely opened? Not just part of one door.

 

The problem with this is the packaging of it. It requires an excessive amount of space underneath the car, thereby increasing the height of the floor of the car, and raising the center of gravity when the car is being driven due to the hollow space in the bottom. This means large moment forces involved in weight transfers, and lots of body roll.

The approach Telsa has taken with the Model X has pretty much all of the advantages of this, with none of the downsides, except that it does require a high ceiling.