The day before, Edwin was there and taught Cole a few things about what made him calm down on the Island. He thinks about soaking in the pond, and rolling the ancestor rock down the hill. Cole wants to prove to Edwin that these things are not going to work for him.
Cole finally tries out going to the pond without Edwin. He hates every bit of it, but he wants to prove to Edwin that going to the pond won't help Cole with any of his issues.
After Cole goes to the pond, he goes to find the ancestor rock and roll it down the hill. Cole hates it and doesn't plan on doing it again. He continues this cycle for many months until it has become normal. He soon realizes that this was not for him to get rid of his anger, it for him to think about what he needed to "do" to stop all his bad behavior.