I found out there are some anesthetics that one doctor may use causing someone to have hellish experiences. The anesthetics cause this burning feeling and their body temperature to go down, making them dream of going to a burning hell. Not to mention, if they are atheists, which they all claim to have been, thats probably pretty stressful to comprehend the possibility of dieing and that being the end of you, never to see, hear, taste, feel or think again. Its I believe psychological and physiological.