The circuit should be monitored by the fire alarm panel and send a trouble warning if the power activating the shut is cut off. The monitoring point of the must be within 6’ of the shunt device. As far as the shunt going off , it by code could be wired either way fail safe or fail secure so to speak, but I’ve never seen anyone wire it where loss of power would kill the elevator. Doing so while code complaint , does not elevate the need for the monitoring circuit. It does however lead to the potential of more entrapments and isn’t good practice. But again I’ve never seen it wired that way, I can’t think of a shunt manufacture for whom it is even an option.