Just caught myself up, and I am still in near awe of how meticulous Lost is with its continuity.  Not just in how the writing itself doesn’t slip into the stupid contradictions that almost every TV show slips into after a few years, but how they choose to reveal stupid little things that lesser shows would never even bother to explain, or if they did, they would do a lot of handwaving and say “BIG REVEAL HERE!”

No, Lost explained a multitude of things from the others slipping repeatedly through the barrier around the Dharma village to Ben’s Narnia-esque closet, simply by saying “we hid the bomb in the tunnels, but those idiots built a village on top of it.”   It also explains how smokey appears out of nowhere to drag people underground.

And, unlike BIG REVEALS in other TV shows, when Lost does it, even in this sort of laconic offhand way, it is very clear that the writers (at least some of them) had this in mind from square one.