MCAT website specifically says they will not allow you to void after you leave the testing center, no matter how extreme the circumstances were. I understand why they have this rule. If they didn't, people could leave, go home, look up answers to all kinds of questions they saw on the exam, and *then* decide if they want the exam voided.
I had a computer glitch yesterday, and the testing staff said they would file an incident report (though I have no proof if they did). They also told me over and over that I was "imagining" a computer glitch--they kept claiming that I wasn't allowed to have access to an periodic table, and THAT was why the computer wouldn't display it (eye roll). I understand AAMC's policy, and think it makes sense. At the same time, AAMC doesn't employ the test center staff/MCAT proctors. There's no telling what line of baloney the Prometric staff feeds students when they run into problems. Promising that they will file an incident report has the foreseeable effect of luring students into a false sense of security that their problem will be addressed.
Personally, I traveled almost 6 hours from home to take the MCAT yesterday, only for the computer to act all screwy. Had I not been absolutely positive that I was entitled to a periodic table, and had I not been absolutely aware of the AAMC policy that I had no choice but to void, and that the most I'd get is a refund, I'd probably have listened to the test staff who claimed I was mistaken about having a periodic table.
All of that is to say: your friend is SOL. If s/he's lucky, they'll get a refund. The score will not be adjusted, voided after the fact, etc., and will be reported to schools. Since the exam wasn't voided, getting a refund will now be much more difficult. YMMV.