"That's..." weird? Concerning? He does not like it. He rubs his face a little bit, as if that's going to wipe away any residual tiredness that's hanging on to him, though he's honestly feeling more energetic bit by bit as it is. Like perhaps a slow drip of energy is starting to build back up now that he's crystal-free. "Hrm..."

That must have been worrying for Kai, too, and after a short moment, he mumbles out a soft, "Sorry, I didn't think something like that would happen."