I was hoping nobody would die but if you think about it they said before that all the candidates that have been brought to the island before died. So if only one candidate is going to "win" it sort of implies some if not all of the others were going to die.
They were on Widmore's list so that screws up his plans too.
It seemed really obvious to me that Locke had put the explosives in the backpack, they showed him helping Jack put the pack on and lingered too long on it. Also it took Locke way too long to get out of the water when Jack shoved him in so he was clearly waiting to make sure they got on the sub. Thought it was interesting he held Claire back, why does he care if she lives? Seems like if he was going to save any of them it would have been Lapidus to fly the plane.
They all accepted too easily that Locke said we can't take the plane there may be more C4 on it, the C4 was the size of a brick it would seem pretty easy to find if wanted to look for more but they all just immediately accepted ok lets take the sub.
It was also sort of an "equalizer" episode, now Jack doesn't have to feel so guilty for the bomb, now Sawyer's actions led to 3 people dying Jack doesn't have to be so guilty for Juliet dying.