It wasn't a feeling that Darcy could explain, but he felt his stomach do a sort of flip-flop at the very suggestion of him setting his sights on Elizabeth. He was sure that it showed in his expression, even if Bobby couldn't read his mind if he wanted to. It was ridiculous - he had the woman he loved, he didn't want anything more than Elizabeth's friendship anymore, but...
Bingley gave him a bit of a side-eye, and then sort of laughed it off on his behalf. "She would eat you alive, Sergeant Sully," Bingley joked a little, allowing Darcy a moment.
"She's lovely. Did I mention that already? Miss Sully is absolutely charming," Bingley was telling him, and Darcy seemed to come out of it again. Especially at the mention of orchestrating a possible proposal between Bingley and Jane.
"Yes, absolutely! That could very easily be arranged, don't you think?" Darcy agreed wholeheartedly. Bingley looked like he wanted to be sick suddenly.