It’s one of those things that’s sort of fun to see them do a lot of stuff where they start sharing something or having personal conversations and one of us comes up and asks, ‘What are you talking about?’ And they’re like, ‘Nothing. Where are we on the case?’ So that’s something that gets teased out. At this time I think that Esposito is a lot more suspicious than Ryan is about their lingering looks and their gestures and glances and physical contact and things like that. I’m actually really curious to find out who figures it out first.
Seamus Dever on Castle/Beckett in season 5