“The Island won’t let you leave”
This is a half theory half question. Is the reason Ben kept telling the losties who wanted to leave the island that they “couldn’t leave” or that “the island won’t let you leave” because they actually COULDN’T because they were in the wrong time period to leave?
Could this be why the Others held on to Walt for so long before letting them go off the island? So that they could time Michael’s mission (of bringing some Losties to the Other’s camp) to be a night or two before the island would be in the right time period for people to leave the island?