I'm not sure if its certain that House only came along because he was curious.
Maybe he was supposed to go, but would House normally react to that kind of a vague demand to do something he doesn't feel like doing? Apparently he wasn't informed beforehand, and from the looks of it he was on his way home, so if he hadn't detoured to Cuddy's office, he'd never have known about the disaster. If he was on call, then he'd have been paged. Nor does he dress in that jump suit thingy, so it's more like he's not on duty there, but simply 'passing by'.