Hell Difficulty Tutorial plot question.

This might not be the best sub for this, but I've been searching the internet for awhile and can't find an answer, so I'm getting a bit desperate. I'd prefer no spoilers but if the answer requires it, then no biggie.

The Emerick guy who wants to kill Nat shortly after floor two starts. Nat says he killed him. Does it ever get explained how? The guy just disappears and maybe I'm dumb and missed it, but does this ever get explained? I'm a few chapters past when it happens and still nothing.

It's really damn frustrating and might be drop-worthy for me. If anyone can answer I'd really appreciate it because I've been enjoying the book otherwise.