Or just jump in front of the car which is supposed to stop and then your companions handle carjacking the immobilized vehicle. There are many ways to normally stop or trick an autonomous vehicle without needing a big red button to stop it. Spike strips are used by police to stop human driven vehicles all the time.
What about if someone triggers it when you're traveling 75 mph on the highway?
I.e. what if someone pulls in front of you on the highway and then stands on the brakes?
Do you have a bulletproof car that can effectively protect the driver? Or are you just imagining Mad Max?