Bruno shows his innocence by thinking of the armbands with the Swastika and the star of David as a cool thing or game.
Bruno knows the boundaries of not entering fathers office because in page 44 Bruno says that. "The rule that applied to fathers office in Berlin was one of the most important rules that applied to fathers office. in Berlin it was one of the most important rules that Bruno had ever learned and he was not so silly as to think that it would not apply here at out-with".
In page 212 it shows Bruno's and Shmuel's friendship because it says that, " And then the room went very dark and somehow, despite the caos that followed, Bruno found that he was still holding Shmuel's hand in his own and nothing in the world would have persuaded him to let it go."