In the model 3 at least, the rear doors can also be opened without power by pulling a cable. Not as obvious as the front doors, I’ll say, but you will be able to get out.
https://www.tesla.com/ownersmanual/model3/en_us/GUID-A7A60DC7-E476-4A86-9C9C-10F4A276AB8B.html
It reads as if the deformation breaks the detection of it being open or closed, which could lead to people driving off without closing it properly. So if it were closed properly it shouldn’t fly open.