Great episode. I'm going to sit back and read your theories (and c&p'd ones) before putting forward any of my own. Apart from
And I thought this (episode 4) was possibly the best ever Lost episode!
Woah, woah. Let's not go crazy here, it was a decent episode but it was no way near as good as The Constant, every one of the season finales, the Pilot, Walkabout and The Man Behind the Curtain