Another person might have reacted poorly to that line being fed to him, or at least rolled their eyes, annoyed. K doesn't so much as look up, at least not until Hakkyuu is holding out the mister.

He accepts it, eyebrows raised in good natured skepticism. "Do you often care so much for the comfort of a genocidal creature?" he asks mildly. And: "Frogs and toads are two different creatures, I'm pretty sure."

If Hakkyuu is going to be sharply sarcastic, K is perfectly capable of being blandly earnest.