It wasn't far, and the Master was starting to get an uneasy feeling that things were not going to be as rosy as he hoped. If Jack was just in a bar, drinking with some random person - or maybe not so random, he didn't know - it wouldn't be a problem. Get him back to their room and let him sleep it off, simple enough.
A glance around the bar as they entered showed no sign of Jack, or anyone else, though if they'd been here earlier, the servers would have cleaned up any mess he left behind.