Well, of course Juliette had to be a mole - if you're Ben, the ruthess leader of a secretive group who wants to keep his secrets, and if you're about to betray one of your closest associates, someone who knows a great deal about you operation, and who would be a major liability if she talked, you don't gas her and abandon her... you kill her.
For most of this episode, I had doubts as to Jack - I thought perhaps he might have gone over to the Other side. At the end of the episode my position changed. Now I have doubts about his sanity. Frankly, Sayid has the right idea about Juliette. (That said, I'm really starting to wonder why no-one has decided that they should send out a small and select exploring party. So far on the island, they've found three (?) hatches, a crashed drugs plane, a pirate ship, a village, a communications post... what else is out there? And what out of that lot can help them?
I don't believe Hurley when he said he was sent over by the rest of the castaways to keep an eye on Juliette. I think he went over himself. Because I'm still sure he's much smarter than he looks. And he's probably smart enough to realise that no-one will ever think of the genial fat guy as a threat (more fool them). In fact, he knows the Others don't, given that they let him go.
I also don't believe anything Ben says. When he told Juliette her sister's cancer was back, that would be a lie. Then, when it was convenient, they showed her the sister 'cured', and took the credit.
What I don't understand is what hold Ben still has on Juliette so she's still helping him. All I can see is that he must still have some other way off the island that he's promised her the use of. Or, at least, that he's told her she'll never get to use if she doesn't help him. (It's also entirely likely that the big electromagnet in the first hatch was responsible for keeping the island shrouded, and now it's gone there's no protection. This may explain why they've just now seen some migratory birds... and so it's possible that a rescue party will just happen by at the end of season seven, or whenever they want to wrap up the show. Or sooner... once they've revealed some big global conspiracy that Jack, Desmond and Jin have to take down.)
