I don't understand what all the confusion is about.
I kill my engine with the throttle servo trim and a manual switch wired to the ignitionm operated by a separate servo on its own channel. I had to use it once when my throttle linkage broke and I couldn't slow the engine down at all.

Came in for an approach, killed the engine and landed no problem, fixed throttle linkage and was back in the air in about 30 minutes.