@Afro Samurai
If that's what you're going for, wouldn't it make sense to make the trigger than he hulks out when his 'heroism' thing is triggered? Else he's going to turn back every time he gets into a fight, and spend his time as a giant monster watching cartoons on a slow afternoon.
The latter half of your statement is my intent. As a 'mutate's' transformation is triggered (or tends to be triggered) by a certain short-sighted flare of emotion (anger, jealousy, etc) and in rare cases a persistent mood (Doc Samson), his is simply something abnormal and not quite useful--as, in his subconscious, he does not feel useful at all as someone whose greatest achievement in life is working at a Chinese restaurant. Initially, he isn't going to be doing much fighting because of the strange trigger; that is, until he gets bored of villains attacking the city all the time and decides to do something about it.
Just as one's psychology changes as he goes through things in life, so will Terell's trigger. Coping with this 'curse' as the OOC mentions is precisely what Terell is doing, just in an especially odd manner. Plus, he isn't enraged when he does change, he's just incredibly bored. Also, it isn't that the moment he is bored he is going to change, it has to be over an extended period of time. It may also happen when he is depressed, and if him reverting to human form while in the midst of a fight is a problem then it may also trigger if the villain (or whomever he is fighting) taunts him, makes fun of him, etc. His transformation is triggered by more than vain boredom.
EDIT: There are people who are genuinely un-entertained by fights or other things normally thought of as 'exciting' if they've seen enough of them. One builds a resolve, and in some cases apathy toward such things--which, as paradox, can also cause one to act and try to prevent said thing while still having no true investment in what is happening. One simply intervenes because he is tired of seeing it.