I think you pretty much answered your own question Yummish. The monster 'passed over' Ben.

It's possible the Others built the secret passage AFTER the Dharma purge, no?

The monster doesn't seem to judge insomuch as spare you if you agree to go along with what it wants. Eko was killed because he refused to do what it wanted. Ben was spared because he said he would. I'd say the motives of the monster aren't really one of a judge but more of a cop. "I'll let you off with a warning…"

No kidding, I'm fairly certain the water vapour thing is bunk.

I think "Jughead" lies in the shadow of the statue.

Huh
Well, this is nice.