well i think i've figured out something plausible... first of all, this is most likely just hypnotism, or in other words a mutually agreed upon play between the exorciser and the "possessed". in order for suggestive hypnotism to work, the receiver must be highly or moderately suggestible. i believe safran is quite suggestible: in watching all 8 episodes of safran vs. god you see safran being OPEN to new religions and worldviews. although he maintains a skeptical outlook during his experiences, he DOES want to experience "the spiritual" through drinking peyote all night, and in another episode says "i hope i really do get possessed tonight" while attending a Voodoo ceremony and seeing others dance and writhe on the ground. Clearly he was open, susceptible and suggestible. as far as i've read, any interviews after this video took place show safran actually believing what happened was real.*
in addition to safran's suggestive demeanor, he gives himself over to the services of an extremely professional, intimidating and psychological bully. this seasoned mindfucker plays on safran's fragile feelings of guilt and filthiness**, while feeding him fear of satan and christ. add to this how scary it would be to be commanded to keep looking into this crazy dudes eyes as he slaps you around with a bible and your done. i felt intimidated, threatened and scared just watching this, imagine now if someone controls not only what you are seeing, and thinking, but also controls your body movement by holding you down? your mind can freak out and will play along if the exorciser paints the hallucionoginic picture well enough.
*although not accepting any particular theology over another.
**remember the catholic father episode where he repents?
Yes, I also believe this is hypnotism rather than him actually being possessed. I also considered it all being an act for entertainment. However, if it was, it would have meant he could easily say "it was just an act to scare you guys!" and be done with it, but he doesn't. You also said somewhere that he believed in it himself, thus hypnotism seems logical. Tbh, if being possessed by a demon means getting supernatural powers, I want that too!