Stupid Merlin, wasn't supposed to voice things that hadn't happened yet. It gave him something like a psychic headache if he didn't say something, but the consequences were usually bad and aside from that - as if this mattered - people looked at him funny, much in the same way that Zach just had.
He sighed as it appeared that the penny dropped and nodded confirmation apologetically, ready to hand over the money until Zach refused him; he would normally have insisted on paying, but money was tight and he had more than himself to think about now in terms of bills.
Zach reminded him of where he was sitting and he got up, drawing his hand out from under a passing foot a moment before it landed there, and then bending to dust off his clothes. "I'm very sorry." he said again, karma demanding some kind of payment.