some time ago something similar happend to me and a friend (the tripper).
Was also a big load, at this time we had no mg scale and eyeballed 50mg.
Smoked in 2 hits through a bong prepared with layers of ash and plant matter.
I sat on the balcony as he smoked in the living room, 30sec. off, he stands up and walks through the room...I was wondering about this. I stood up to get inside, and as he saw me...
afterwards he said that he was in his own mind-bubble prison and after I got into scene, with hair out of fire, he was plopping out. He ran through the room and fell on the ground - then sitting and screaming "I AM ALIVE" ...at this point i wasnt sure that this is my friend who was screaming because his voice was so different. He stood up and I tried to calm him down...he was jump-hugging me..and drew on my hair...he said behind me were many of our friends and gave energy as i drew him out of the bubble...i layed him down and sung some OM and Arut perum jyoti mantra...at this point it was nearly over and he just wanted to hold my hand for some time. 2min later it was back to "normal".
Some back pain for me and an broken rip for him from his demise.
Never got any other one with such reaction...
EDIT: at this time he was on some tilidin (100mg daylie), but not on this day.