Because you're clearly exhausted, that's why. [It really wasn't a subtle shift in conversation. He's sure that if Kokichi were on the top of his game, it wouldn't have worked. He would have caught on and shifted the subject on to something else.]

You can't even lie convincingly in this state. Seriously, when was the last time you had a decent night's sleep?

[Don't make him break down how he knows you're lying, Kokichi. Because he will, but you probably won't enjoy it.]