^^^This is the best way of doing it I’ve found. And as above, you don’t need a valve key. Just a flat head and something to cut the tube. I’ve even just ‘pulled off’ the zinc tube in bits with a pair of pliers before. It’s not ideal, but the metal is soft so you can grip it with pliers and twist like a Spam tin.
You could unscrew it and put the tiniest amount of the weakest locktite on the threads. All you want to do is create enough resistance to stop it turning with recoil.