Sayid disappears from Ajira 316, Sun is left behind

As Frank stumbles out of the cockpit into the cabin, Caesar is seeing if Ilana is okay. Ilana looks panicked when she notices Sayid is gone. He disappeared from the plane with Jack, Kate and Hurley. It turns out that Sun is still there though. She and Frank wonder where the others have gone when Ben pops in a says in his creepiest voice "They're gone." When Frank asks him where they've gone, Been says "How would I know?" I'm guessing he has at least some idea of where they could be.

Since Sayid was flashed into 1977 with the others and Sun was left behind, does this mean that she wasn't supposed to come back? Or, does this mean that her path to helping the island is in the present?