Desmond's Sacrifice
What will be Desmond's sacrifice? He's Lost's equivalent of LotR's Ring of Power, and those energy pockets are Mt Doom. Think about it. The energy pocket created his power in the hatch explosion - the Ring of Power was created in the Fires of Mt Doom. Everyone is fighting over him. To fix everything, he must be destroyed by being cast into the pit of energy.
.........
And Claire is Gollum.
The Last Temptation of the Christ vs The Alternative Reality
In the Nikos Kazantzakis book (and possibly in the Martin Scorcese movie - I've never seen the film version), the titular Last Temptation is offered to Jesus by the Devil while he was in the act of dying on the cross.
In this Temptation, the devil offers Christ a vision of another reality, a reality in which Christ foregoes the like of a martyr, and instead lives a quiet, peaceful, "normal" life in his home village. He takes a wife, he raises children, he has friends and a community, and lives on for decades into his old age. After many years, he comes to understand that this is all a fantasy: a vision of a life he had to give up in order to fulfill his fate. The Devil tells him that he doesn't have to be a martyr, that he can abandon his d…