Juliette's death was one of those hard to watch scenes. And the fact that we had to watch her fall down the hatch several repeated times(thanks editors! and pre-premeire recaps lol), see her survive buried alive in the hatch remnants, and then die in sawyers arms was an emotional roller coaster.
I thought it was really nice when Sawyer asked Miles to stay behind. I thought this was going to be the beginning of an interesting friendship pairing like Locke/Boone. But, a few moments later when Sawyer ask Miles to communicate with Juliette, Miles realizes that the con man has struck again.
This moment mirrors our ALT scene with Sawyer and Hurley on the plane where Sawyer warns him that he shouldn't divulge that he won the lottery because people will try to take advantage.
Now back to MLT. Miles leans down to try to communicate with Juliette, and what do we hear? The smoke monster sound effects and Juliette stating that "it worked".
Now, at first, all the leading events would lead us to believe that she was telling him that the bomb explosion plan worked. But this is where I have a new theory.
What if Juliette was working along side with the MiB, thus explaining the Smoke Monster noises. What if by "it worked" she meant that Smokey's plan worked to kill Jacob. Most love Juliette and myself included would hate to see her siding with MiB. But they do share similar interest. Both want to go "home" and feel trapped on the island, directly or indirectly by Jacob. As Jacob is the leader of The Others, and Ben at the time of his leading The Others would not let her leave the island.
This would also explain the Smoke Monster noises as Miles was communicating with dead Juliette. What if Smokey was communicating with Juliette that Jacob was dead. Thus freeing The Others from their leadership and the "rules" keeping them on the island.
In theory, MiB would want Juliette to help cause the "incident" as this event caused a domino effect that led to MiB achieving his long awaited Loop Hole.
The next question to ask would be when, in the timelines, would Smokey and Juliette have started working together. And if this proves true, was Juliette voluntarily aiding Smokey, or being used as a pawn in the same way as Ben.