Derek largely spends his time waiting in lines by scenting his surroundings surreptitiously. Sometimes, he looks around — which at some point he does, catches Felicity, and smiles back, giving her a wink — but mostly, he's using his stronger sense to gather information.

He's admittedly thankful when she turns her phone over face down upon his return. He wouldn't have minded if she hadn't, but it's an indication that she's actually invested in his company, he thinks, when she does and Derek likes that. When Felicity leans in, Derek leans in, too, smirking a little.

The smirk settles into something a little softer and more genuine, though, at her question and he nods. "It never leaves this conversation," he promises sincerely before sitting back a little ways to give her a little bit more breathing room. He doesn't pull back too far, because he assumes she wants to keep her tone down, but he also knows that she's going to probably assume that his hearing isn't nearly as acute as it actually is and he doesn't want her to feel like she has to raise her voice more than she's comfortable doing.