"At the back of his mind formed the uncertain outlines of an excuse. He muttered something about a swim and broke into a trot"

This talks about when Maurice kicked the three littluns sand castles, you can see that he still has morality and inocence left and wants to have an excuse for this savage act even thought there are no rules or adults to tell him to do so. Later on this remorse disappears when his beast comes out (page 60)