Christian seemed a little skeptical and he looked everywhere but at her before he said "Yeah... well if you're ever in Utopia just give me a ring or something..." obviously a joke. He didn't have a phone and Utopia definitely didn't have a phone.
"I should get back before McGuire gets suspicious and does something stupid." it was true, the man might run out and get himself into trouble or something. He could get the police called on him pretty easily just by existing in some places. People didn't like the homeless to come near their places of business or anything like that... probably because it reminded them how much of their lives they took for granted. "Thank you by the way." he jostled the bag so she would know that he meant about that but he was obviously signaling for them to go their separate ways.