regardless,of the safety factor,,,which is very important,,,theres still a reason that ,he cant shut it down,via the choke,or throttle ,and that needs to be corrected,and yes,the kill switch will definitely add to making things safe,sometimes in the confusion of an emergency ,its good to have several ways to shut down,but the description of the problem seems typical ,of an air leak,and not the need for a kill switch.
ORIGINAL: TURBINATOR
I would feel much safer putting an optical kill switch on a gas motor to shut it down instead. This will prevent accidents both on the ground and in the air should the need arise to kill the motor quickly. I would of thought TBM would have suggested this.