This wouldn't even work, if the person themselves needs to see their actions as a threat, then it's already faulty. A Jihadist/Suicide Bomber's brain wouldn't be scanned with the intent of malicious actions, they would see justification in their actions and thus not be a threat, if the scan works the way I think it does. It would most likely look more malicious intent within the brain activity but if someone fighting for a "DIVINE" purpose feels what they are doing is just, then they will easily bypass the check.

For some extra reading material I suggest The Technological Society by Jacques Ellul.

‘We found a tumor. Would you mind coming down to the hospital with us?’

You maniacs. God damn you all to hell.

https://www.youtube.com/watch?v=sPbjPOgRtyA