At no point is Cayde unaware of Ianto's presence — if the guy wants to stand around and listen to the story of three guardians who were total badasses, who's he to stop him — but then he seems pretty awkward about the whole thing. And painfully normal when Cayde actually turns to look at him, but who's he to judge?

"You okay there?" He tilts his head, glancing past Ianto to see if there's anyone behind him or whatever, "get lost? It's real easy to do in here, no need to be embarrassed."