[he seems startled by the casual kindness, maybe a little more tense and wary than he should be (it's just a water bottle, he saw clearly where it came from, a stranger mutually helping out doesn't have any reason to not be nice...?)

after a moment he does reach out and take it, though, flashing Kim a smile that doesn't seem entirely forced, before unscrewing the cap and taking a long drink]

--ah, you're right, I did need that. Thank you.

[and, hurrying on as if to gloss over that brief awkwardness]

I know what fireworks are, but all this, um, packaging on everything is pretty unfamiliar to me. These aren't as bad as the food stores, though.