Because I would think that’s already been thought of, that of the car needing to stop from an internal request of an occupant needing assistance. What does the car do if an external threat is acting violently on the car, such as trying to run it off the road? I suppose the best thing for the car to do is automatically reduce speed and stop moving, to end the scenario. But if the malicious car’s occupants get out and seek to enter the self-driving car, what do the passengers do? They have no recuse for safety or self-preservation. The car is no longer moving and exiting the car provides them with less protection than they have.
And the point is precisely that occupants can’t defend themselves in the event of an attack. I don’t see any defense here. At least if you are helming the car you can do something to evade the attack or leave the scene.
