As soon as the person in the corridor speaks, it's Light's turn to blink. That's narrowed it down; the voice is accented, but recognisable from the Ls who've appeared here and there. But the wording, and the subject matter, and the fact that this is an L with a gun sounding like a yakuza—

Those translate as different, and that difference means he needs to forget the little he's learned about Ls, and take this one as something entirely new.

"That's a difficult one," he calls back. "I'd have to say that I'm my superior, here. If you have an objection to politeness, I'll keep that in mind, certainly." As he speaks, his hand has gone not to his sword hilt, but to the heavy knife sheathed beneath his sweater. "Are you aware of your situation?"