How do we know the hatch is destroyed? All we saw was a metal door come falling down at the beach, presumably blown there by whatever Desmond triggered when he turned the key. But we never saw the result of the "event" on the hatch.

__________________
Things fall apart, the center cannot hold;
Mere anarchy is loosed upon the world,
The blood-dimmed tide is loosed, and everywhere
The ceremony of innocence is drowned;

--Lines 2-6, "The Second Coming" by Wm. Butler Yeats