To say that consciousness is the only thing we truly can know exists- this does not go far enough. I liked his example, that we can question whether we're really happy, but when we're in acute agony, there is no question. It is that precise aspect of consciousness that alone survives all skepticism. Suffering then forms the bedrock of what we can safely say, that we can, just maybe, know (probably) exists.
So, why fire? It's extremely dramatic, but that's in part because we know it's extremely painful. We know on deep physiological level, that burning is to be avoided. At all costs. Immediately. It takes a whole other level of willpower to endure relatively minor burns, especially without even flinching. If suffering can be escaped, what better way to prove that you've done it. You've achieved the very pinnacle of the religious experience, transcending that last step of what the rest of us mistakenly think is real.
The contradiction therein being that if you've gotten that far, why do you care what anyone else thinks? Why are you trying to prove anything to anyone? The social causes often involved would further suggest that social recognition plays a role. Sure, it's still an amazing feat, but Jesus Christ.
As if there's an even deeper bedrock of what's real. Some find it easier to meditate while burning alive, than to let go of what we think others think of what we think.
Yeah, yeah, I'm stoned again. So what :p