[...He couldn't help it, that smile was infectious. It always had been, even when things were so desolate in that prison camp. It was nostalgic in a good way despite the unhappy circumstances it made him recall.]

[His smile is light and humorous. He laughs, shaking his head.]

I guess there's no point in arguing with you, either, huh?

[He offers him back his empty glass.]

Here- I don't want to waste more of your alcohol. It doesn't work on me anymore.

[A roundabout way of confirming what Cliff might have assumed about him. That they did experiment on him, that he's been altered.]