"Are you listening to what I'm saying? You haven't been abducted - or not any more than I have." Light's eyes itch, but he doesn't move. How thick are the walls - or rather, how dense are they? Would they stop a bullet at close range, or not? Not unattended - are there more people in the corridor? Impossible; Light would have heard that even more plainly.

It's clear that L-in-the-corridor either doesn't recognise Light's voice, or is pretending not to, and that thought is what leads him to introduce himself. "As for my line of work, somehow I doubt that we share one. I'm a doctor. My name is Light Yagami. I was brought here the same way that you were."

Which means, he adds to himself, that I have information you need. That's got to be worth a thing or two.