So even though the O6 returned to the Island it's still jumping through time. I think the season finale will be Des (and Aaron? and Ji Yeon?) arriving on the Island in his sailboat with Penny and Charlie (assuming they're alive, anyway) and thus completing the circle and stopping the spinning.
Did they even mention Sun's child in this episode? It's weird the others wouldn't even ask. Don't tell me she drowned him in a tub too?! But I guess he's just with Sun's mother.