Costigan watched silently as Bakura moved toward the exit, a light smirk appearing on his lips at the idea that either of them were ever more talkative. He didn't know the other guy too well, but both seemed more keen on letting others do the talking and simply taking it all in. It didn't work well for conversation.

Just before the other guy could disappear, Costigan called out to him. "Hey, Bakura. Don't come here again."

It wasn't exactly a threat. It was, by sheer nature of being a command and suggesting that the alternative was unpleasant. Yet, there was no animosity behind it and Costigan didn't feel too strongly about enforcing it if the guy did actually show up. It was something they could deal with then, if it had to happen.