[he can sense something is off, but not what: he doesn't quite know her well enough yet. he just has realized that Celeste's formality is a mask, and there's something she's masking. he's not about to try and make any assumptions as to what: they're both too complex to demean each other with meager guesses]

Tch. You think that's repression, you should have met my brother Luther. Ten times worse.

[he reserves his judgement on her 'interest' in Ryou until she's said more. ah. her interest lies in his relative innocence to the rest of them, then. Horatio does have to agree it's fun to push a button or two and watch him squirm, but in a teasing way. this darkness she's showing him is something else. something that shows that at some point, she lost so much control that she needs to lord it over others in ways they won't necessarily notice. where only she will know she's in control. instead of shock, fear, disgust ... Horatio simply thinks back to the conversation they had climbing up from the basement in the forest. of how they each had stories to tell. he wonders what they did to her. how deep that fault line of hurt runs.]

Tell someone you want to beat him at a game he takes a lot of pride in, and it's never going to go well.