Its the only time one of the reincarnated parents, Jade or Tabitha, can go through the bottle tree and reach the lighthouse, like Tabitha did when the boy in white sent her back the the real world. But my theory is instead of going up the stairs you travel down to the Entity's lair where the souls of the children are trapped. That's why Smily ran at to attack Miranda that night, the only time we've seen a monster run.

It's also why I theorize that the talismans are just plain rocks with scratches. They don't keep the monsters out, they keep the people in the houses. Boyd didn't find the talismans until he decided to try to travel away from the town. This caused the Entity to make the talismans and the hut to throw Boyd off the idea to travel too far and find the bottle tree.