The peculiars and Miss Peregrine (still in bird form) get back to the house to find that it's destroyed from the bomb. It's now time for Jacob to decide if he wants to go back to Florida where he has a high risk of being killed or he can stay with the peculiars and have a lower risk of being killed. He decides to go with the peculiars but not before saying goodbye to his dad (in his own unique way). Miss Peregrine tried to cahnge into her humand form and she found out that she cannot.
The passage way in and out of the loop is a main symbol. It's a cave that in hidden in the deep of the forest in the island. It symbolizes Jacob's decision to either stay with his family and go back to Florida or stay and leave with the peculiars. Every time he goes through the cave, he thinks about the decision he knows he has to make. It makes him feel bittersweet.
The peculiars, Jacob, and Miss Peregrine decide that they need to leave. They found boats and rowed away from the island. The loop was destroyed so they are currently in the past; the year is 1940. They keep rowing until they find land.