Ideas on a kill switch for my car

I am trying to visualize how to develop something in home assistant that will shut my car down, when it goes from connected to my wi-fi and then disconnected. But only only when I set a virtual switch. So in theory, I would start my car up(while connected to wi-fi), then I would “arm” my car. If the car loses wifi connection(without un-arming) from my network, it would activate the kill switch and shut the car down. Is this a crazy idea? Any ideas on what hardware to use? I was thinking of a simple nodemcu.