Something to keep in mind with this method is if you fail and there's damage, it's not apparent right away like with other methods. It takes weeks or more to see the full extent of the damage. Depending on time exposed, purity of gas you were exposed to, etc the damage can be mild to debilitating. You can have severe memory problems (to the point you can't function independently), cognitive deficits, drastic mood and personality changes, physical problems like migraines and headaches, etc. these issues can still be absolutely debilitating without being a "vegetable"- just because someone can breathe on their own doesn't mean their quality of life isn't shit for them.
It's why for me personally this method is off the table- I'm far too anxious to deal with that if I failed (also editing to add that I know every method has consequences if you fail, but most of them are pretty immediately apparent- it's the waiting game I couldn't handle.)