It's been stated by the producers of 'Lost' since the beginning that somebody was going to die before the season ended. And with the plane "crash" last week, it's beginning to look a lot like it's Boone Carlisle who's going to buy the farm.
In the promos for next week's episode, Boone begs Jack to "let me go". When they first crashed on the island, Jack was totally against the idea of mercy killing, and only dispatched the federal agent because Sawyer botched it when he stepped in to do it.
But they've been on the island now for a few months now. Such a hardship could change a man's way of thinking. Maybe Jack would ease Boone's suffering and help him cross over to the other side.
Or it could be that Jack will stick to his Hyppocratic oath - isn't the title for next week, "Do No Harm"?
So someone else has to step up to the plate and relieve Boone's slow suffering death, and there are three possibilities:
Shannon - out of her too-late realization of how much she really did love her step-brother, she kills him.
Sayid - because of his feelings for Shannon, he agrees to her request to do it using the skills he gained in the Republican Guard.
or my personal favorite because it's kind of out of left field.....
Sun - with her knowledge of the various plants on the island, she must know of something Boone could chew on that would kill him and end his suffering. And I think she has the "compassion" to help him....
Hrmmm..... the three "S"'s
But then again....... what if the promos are misleading? What if we're only being led to believe that it's going to be Boone and we're being set up for a bigger shock of a surprise?