Tom came, he saw, he chewed gum and he flexed his bicep. Not to mention summing everybody up in one diary room rant and then disappearing for a steak and chips. I think he did the right thing.
He couldn't say anything without swearing, he seemed more of a poser than anything else and I think he went because Noirin became involved with Siavash.
He seemed to be spending all of his time to try and look cool rather than contribute anything.