Short version? "Dreamz" isn't picking between a chance at a million dollars and maintaining his integrity. He's picking between a chance at a million dollars and maintaining his identity. This is how he sees this choice.
On the way to tribal council, "Dreamz" voices over that it's a choice between a million dollars and keeping his word. Which is, of course, completely untrue, unless you assume that if he keeps the necklace, he'll win with the jury. But I think he has himself convinced, probably partly based on Boo's comments at the last tribal council about his popularity and likely "sympathy votes," that it is the case and he will win the money as long as he keeps the necklace.
Everyone sits down at tribal council. The jury enters. Boo hasn't shaved yet, I don't think. If he did, he decided to stay with Mountain Man for the final tribal council. ["Oh, he trimmed things up. With fiiiiine results." -- Joe R] Jeff informs the jury about the fact that this will be the last tribal council where someone is voted out, and that the jury will face three finalists. Jeff then says, "There's really only one topic to be talked about tonight." And what is it? It's whether "Dreamz" is or isn't keeping his word and giving up the idol. "Dreamz" announces that he's been thinking it over, and it's a game about lying and backstabbing, after all. But, of course, he says that when it involves "your humanity," you find yourself trying to "do it according to your friendships." Huh. I’m not sure it's "your friendships" versus "the truck you already took, which is worth sixty thousand real-life dollars," you know? Jeff basically tells "Dreamz" that he took the car when he wanted the car, and now that it's time to deliver on his half of the deal, it's maybe a little tougher. "Dreamz" says that indeed, he "really wanted the truck," and -- note well -- he still wants the truck. But Yau Man made the deal out of strategy, "Dreamz" insists, acting as if this is a great discovery and that Yau Man somehow denied that he expected anything in return. "Dreamz" says that if he gives up the necklace, he goes home, and Jeff asks him why he assumes that's the case. "Dreamz" says he's sure he's right, but he's "prepared for that."
Jeff asks Yau Man whether he had a discussion with "Dreamz" trying to prod him into keeping his word. Yau Man says he didn't think "Dreamz" needed any help figuring out what to do. "I left him alone to his own volition...to decide." Jeff asks Yau Man if he thinks that "Dreamz" will live up to the bargain he made. Yau Man says he thinks "Dreamz" will keep his word. Yau Man says he wouldn't say that about everyone. Jeff asks Cassandra what she thinks "Dreamz" should do, and she says she thinks he's in a tough spot. Jeff asks Earl if he talked to "Dreamz" about it, and Earl says he left "Dreamz" alone, pretty much. Earl says that it's tough to pick between "integrity" and "the game," because it's about "what matters to you most as a person." "What would you do?" Jeff asks, and Earl immediately says, "I don't think I would have been in this situation." Well, no kidding. Earl wouldn't take the hedge bet. He wouldn't need to, and he's too much of a gamer. Also, he'd instantly know that the jury would hate him if he reneged, which I think "Dreamz" decided not to think about.