Jack will err on the side of making friends. Life is more convenient overall that way. When the kid refuses to take his hand, though, he doesn't dwell on it. Hardly important, in the grand scheme of things.

Following him, though. That will have to be addressed. "I am." Jack tilts his head to the side, confusion and perhaps a touch of pity. "Didn't we just do this?" He places a hand on his own chest. "Jack Harkness." Then he extends the same palm in Barry's direction. "Malcolm Merlin." Back to his own chest. "Very busy, lots to do. Excuse me." He tries once again to move down the hallway, figuring that if there are any unbiased answers to be had, he won't find them just outside the official offices.