This and other Season 5 episodes prove that the writers of Lost did not just "make it up as they went
The payoffs in this and other recent Season 5 episodes were set up long ago in earlier seasons.
That proves they could not have merely ad libbed Seasons 4 through 6, as some critics have alleged.
The only other time I watched Lost was when it was was first broadcast. At the time I too felt as if the writers painted themselves into a corner in the second half of Season 4.
I no longer feel that way.