Then how does the door stay closed?
You're thinking of the door latch, not the door lock.
the lock works differently than many other cars, but there's still a lock.
Again, there is no physical locking mechanism. That's what's different from any other cars in history.
Here's an article that talks about how the manual release works
The mechanical latch is on the interior of the vehicle, thus bypassing any "locking" methods. You can't do the same on the exterior.