Embarassing boners in public

My friend is a MRI technologists and he says it's not uncommon for men to be getting an MRI and get an erection while they are in the imaging scanner. Those machines require stillness so depending on the part of the body that is being scanned they sometimes have to redo the scan. He says most guys get embarrassed especially if there is a female technician present but sometimes they play it off as if it didn't happen but of course the technicians see it all and try not to make the patient feel awkward about it.