I failed because it took too long to pass out and my survival instinct kicked in. I spent many days after throwing up and feeling like shit. I don't think it caused any brain injury tho, and I was in there for about 20 minutes and I'm sure I was about to fall asleep before I panicked and left. I'm gonna try again soon. I'll have a lot more charcoal burning this time (just in case) and try to relax in there playing games or something.
Edit: I tried to do it on a fairly small bathroom, I know it's very dangerous because I live on an apartment and neighbours could be injured, but I don't have a car and can't even afford a tent lol, so... Maybe i'll schedule an email to my local firemen to be sent about 5 hours after I've gone in.