He's smiling, relaxing now that the wolfsbane is in his hands and the transaction is nearly complete, but when the girl is suddenly taken ill Colin can smell as well as see the evidence of it. Sour scent of stomach acid rising up, and remembering his own nausea after smoking the dank, uncured plant, for an instant he wonders if touching it has affected her. But no, of course not. She's human. He can smell that, too, the faint but unmistakeable taint of the curse, though it's been a while since he's crossed paths with another such as himself.
"Anythin' you need." Colin reacts quickly, setting the bundle of purple flowers aside and offering her his arm. He's watchful, ready to catch her if it comes to that. "Just over here." One of the posh town houses had a sort of wee decorative wall around it, about the right height to serve as a seat.