Lost, Season Four, Episode 10

When Jack?s health is seriously compromised, Kate and Juliet must learn to work together in order to save him and something goes wrong as Sawyer, Claire, Aaron and Miles continue their trek away from Locke?s camp and back to the beach.
Ryan’s post.

Claire disappears, leaving Aaron behind? What time period is the Kate/Jack flash-forward? Before or after his suicide attempt on the bridge? Jack reminds Kate that Sawyer “chose” to stay on the island?
I continue to be confused.