I've watched so many of these burning alive videos it's fascinating. In every one of them the victim is completely calm before the fire starts because they already accept that they're dead. They're probably thinking "it's already over, I just have to bear a little more pain and I'm out of here", but as soon as the fire starts they go crazy like they couldn't prepare for it no matter how much nihilism and apathy they built up. I always try to imagine what it feels like but it's beyond my scope. Truly a once in a lifetime experience.