Lost: Man of Science, Man of Faith

Kate: "Kind of unlike you, the whole glass half full thing."Jack: "There's a glass?"The lights are on and somebody's home. Somebody that Jack apparently met long ago, when he had bad hair and a worse bedside manner. Yes, we finally got some answers, but this wouldn't be Lost without yet more unanswered questions. How long has Desmond been in the bunker? (Yeah, and why, and how, but how