Clearly it wasn’t. Imagine the car in this story had contained a person who’d just had a heart attack. How would the cop (or a paramedic) safely provide emergency assistance?
This car had no passengers so that would be a moot point here. I’d hate to see self-driving cars programmed to defend themselves at all costs even when they were unoccupied.
If you really NEED to do some kind of defensive maneuvers in that kind of rare situation then, I dunno, maybe switch it to manual driving mode?