So there's no guarantee that this will rid of Hai of Peter after all. He may not have bothered to try at all if he'd known there was a chance he still wouldn't end up getting what he wanted out of it. That's all this is for, after all. Yes, he does feel a little guilty that he's using Yesung (and by extension, Kun-woo) but not bad enough to not ambush him. He and Yesung aren't close enough for him to want to risk his solitude for him.

Sorry Yesung.

Hai is already approaching the door when Peter knocks so it isn't terribly long that Peter has to wait before the door is pulled open. He does nothing to hide the hint of disappointment in his expression at seeing that Peter really did show up. Though this is all a means to an end (possibly), he still hoped that nothing would come of it. Some just have no luck. "Come in."