FWIW, check auto immobilizers versus kill switch. For decades most of our fleet had an immobilizers switch wired into the console, just a simple red switch among a dozen other switches.
If the car was idling and in park and the switch activated, the car could idle (a/c, heat, lights, etc) but if someone tried to put it into gear the car died and wouldn't restart until the switch was deactivated. Same thing if the switch was activated when the car was off, it wouldn't restart until activated. Never had a problem except when someone went to move the car and didn't know about the switch and it died........Goodluck