[Hmm. It's hardly a question, more a sigh of it maybe, dry as he's contemplating Shiro's words in the back of his mind, as though he could piece it together to fit somewhere in the blanks somehow. Predictably, it doesn't work for much and there's resignation in his shoulders.]
I don't know what to tell you. It's as if something's just slipped right through my fingers and that was it. [He can recognize vaguely that this conversation started because he remembered enough. And now, already, he doesn't. If that's not unnerving as it is...] I can't explain it or understand it.