For some, being placed in the MRI would be torture. Hope you don't have a plate in your head or other bodily location. Would torturers be so concerned with this, or is that just part of the threat.
TLA person: Give us the code or we put you the MRI machine!!
Victim: Can't you just use a $5 wrench instead?
No, I think that adding torture to the mix will make the FMRI results even less readable
What I was thinking was using FMRI to find out if they actually do remember the password (FMRI lie detection really only works with yes/no questions, AFAIK). If they don't know, then torture is a waste of time. If they do know, then you know torture may be fruitful.
FMRI uses indicators like pulse, heartrate, etc. to make a more or less estimate on the truthfulness. Torture can make these indicators useless.
Torture is a very flawed method to extract informations. You can't be sure that the victim isn't telling lies or admits to crimes just to make the torture stop.