There is no actual safety switch. Instead, the shifter position is communicated via CAN bus to the ECU, which, in conjunction with the SKREEM, will grant Drive Authority, and hence the ability to start. The starter signal does originate in the ignition switch, but that is a signal that goes to the ECU, and the ECU decides whether or not the starter may be engaged. Hence Soft Start is an option that can be enabled (and is on many automatic Crossfires), and why the starter will not engage when the engine is already running.