The most sincere way possible

Fuck off

Oh, apologies. I misunderstood your comment to say "this and the entire S&M album are great" when you meant in addition to the Apocalyptica song.

That wasn't S&M, that was a cello quartet called Apocalyptica covering Nothing Else Matters. S&M is a great album though.

They do give a few clues, that are a lot more apparent on a rewatch. In the episode Dead is Dead, where MIB as Locke leads Ben to be judged, he disappears completely, the smoke comes through the vent, goes back, Alex shows up, disappears, and then Locke finally show up again. It's easy to dismiss on a first viewing…