Rushing into the pond is likely just a way for Peter to try to one-up Cole and look tougher. However, Peter’s relaxed demeanor later in the day suggests that the pond still had a calming, healing effect on him. His insistence that he doesn’t want to get used to it, meanwhile, sounds a lot like something Cole would’ve said a year ago. This suggests that Peter is going through much the same process Cole did, and that Cole could help Peter if Peter was open to it.