I have. I followed one of those guides that made me buy a tank of gas, a mask, and a tube that connects both of those objects. The gas was already in my system and since my body didn't know the difference between that and air, I was going faint in a matter of seconds. I knew nobody would find me because of my location and timing, so that moment was probably the last time I would be able to think. What ended up happening was that, although I was already knocked out, the tube burst and allowed me to breathe actual oxygen, and I later woke up with tears and a massive nosebleed that didn't stop. I don't plan on trying again, since that was supposedly the easiest way to go, but one thing is for sure... that moment where you're close to death. Even though, to some people it may be nerve wracking and scary, to me it was pure bliss. Like, all the weight that was ever on my shoulders... lifted. When I woke up, I cried with a feeling of disappointment but overall happiness. This is because now I know that, if things go real bad, all I have to do is do the same thing, but buy a more reliable tube. Makes me happy knowing I have a painless escape route.