Agreed. Being in an MRI sounds like you are in the middle of a warzone. With constant sounds that sounds somewhat like gunshots. That would be pretty terrifying on shrooms.
You also cannot move or else the resultant images will be blurry.
I have a pinched nerve in my back/shoulder that becomes very aggravated when laying flat on my back. It took 45 mins to do the MRI and we managed to not have to do any re-takes. I was so uncomfortable from eating the pain that I threw up as soon as I exited the machine. I simply couldn't imagine someone who is tripping trying to sit still that long (ignoring the auditory/spacial effects all together).
it sounds like being on an airplane next to one of the engines. constant woosh. nothing at all like a warzone, or even a moderately busy range.
would be disconcerting as hell on drugs, but that's cuz it is even 100% sober -- it's a weird experience being in an MRI.