They are going to have to change the name from three skeleton keys to SIX skeleton keys, hehe SIX skeleton keys.
The Rats from the ship smell the fresh meat inside the lighthouse so they try to find a way in and when they can't they just cover the whole lighthouse.
Why did their light turn off?
Maybe they're dead?
One night in Itchouad's room the window breaks letting all the rats in they swarm all over him and the two other men come running when they hear him screaming and they freak out over the rats.
Say in there a little longer we will come back tomorrow.
They run away and up the stairs into the gallery or where the light is stored. While running up they kill the rats that lunge at them with their knives and they also kill the ones who get in the gallery with them. They close the metal trapdoor after they get up there and they sit up there for a while. Le Gleo starts going mad.
They decide not to light the lighthouse tonight because they think somebody will notice them if they do this and when they come they can save them.
When they see the boat they decide to signal them in morse code by turning on and of the light.