I believe that the "system" would have the required algorithm necessary to prevent stuff like that happening.
But yes, I believe it could be the source of quite a lot of drama if somebody could force him to choose specific things. But I don't think that people will know about his ability to the extend of knowing that there's a pop-up message system. If, however, I were to observe from afar (...Pun... not intended? I'm not certain myself.) and see that his ability copies most elements from video-games (Or saw that he points at random directions as if pressing something), I would get interested.
But I do not know what the message says and I don't know if he's lying about what the message says. A Gamer's mind would help him to be calm during the procedure, so torturing him wouldn't work. And what if the message is something like "A vicious NPC is endlessly harassing you. Would you like him banned?"? Then I'm royally screwed if he pushes that bottom, for the planet itself will spit me out like a gum.
Out of freaking orbit.
At Mach 7.
If you had super-hearing, anytime now, you be hearing a "pop".
(...Superman vs the Elite.)
Being able to stay calm doesn't prevent him from feeling pain so how long it will take before he will just want pain to end, week, month, half a year ? what if they torture his friend ? staying calm won't help him if he doesn't find way to rescue his friend, I don't think he would be able to say no if his friends are tortured.
Of course there is always possibility that bad guy forces main character to press button that will screw up bad guy XD.