In the beginning of the movie, it is possible to watch some specific actions that Max made, like the moment when he built an igloo and his sister’s friends destroyed it and hurt him when they play with him.
During his adventure has a similar situation, but from another point of view where he motivates to hurt one of the monsters, Alexander.
With this in mind, it is possible to see that the beginning of the movie before of his adventure, all the situations happened are similar or equal as the situation with the monsters in the island.