Kaoru almost certainly wasn't lucid enough to process what was going on, confusion making itself present in his expression as the knife left his skin. He was expecting pain, or perhaps something worse, but all he felt was a stinging at his neck.
He winced at the touch, and he was completely out soon after, going limp on the ground.
When he did finally wake, he jolted up, wincing as the metal of his knife dug into his thigh. He raised a hand to his head, shutting his eyes tightly as he tried to get rid of the pounding sensation.
...Why wasn't he dead?
Slowly, he looked around, finding that he was somewhere completely different. The sun was slowly rising in the sky, and he had to wonder if he'd really just been lying here all night?
Cautiously, he raised one hand to his neck, feeling the dried blood along the length of it. What happened?
The vampire he'd fought with was nowhere to be seen, and he groaned as he pushed himself to his feet, taking the knife out of his pocket and putting it somewhere safer. His phone was dead, and his watch was cracked, but... he was alive? How odd. He began to walk in the direction of what, he hoped, was back to headquarters. Desperately needing a bath... and maybe something to eat.