That plan is half-assed. You’re gonna fuck up the attempt mate, and I don’t want you to end up worse than dead.
It’s a fairly peaceful method if done right. The method can knock you out real quick (10-30s for a humam if done right), but it takes a while to actually die from it (could be 30min depending on lots of factors including gender). A lot slower than you would expect. I’ve seen gas termination with rats for anatomy lessons. It took a tiny animal a long time to die. 15min minimum, so we chose 30min to be sure. A human with 5L of blood rich in oxygen takes longer. In between losing conciousness and death, you’ll fight back. The odds of surviving as a half-vegetable aren’t favorable here.
If you choose to go, make sure you rethink this method.
Christianity is just as much a festering wound on society. Actions like beheading because of some religious zealousy should not be tolerated.