Umbridge treats the Centaurs poorly, insulting their intelligence and traditions, but the Centaurs refuse to accept this kind of treatment and challenge Umbridge’s rash demands—something the bullied Hogwarts students are unable to do. The Centaurs, unlike the students, aren’t cowed into submission by the power of Umbridge’s credentials. Since the Centaurs operate by their own rules and don’t respond to any lone governing body, such as the Ministry of Magic, Umbridge’s credentials and titles are meaningless to them. Instead, the Centaurs have established their own system of justice, which seems to change depending on the circumstances. When Harry and Hermione were in the woods with Hagrid, for example, the Centaurs left them alone, deeming them “innocents.” Now, even though only a few weeks have passed, they find Harry and Hermione suddenly too old to be shielded by childhood. The Centaurs’ rules are pliable, but cruelty generally begets cruelty, and Umbridge is finally, rightfully punished for her arrogance and presumptiveness. Umbridge has brought so much unhappiness over so many months, but it takes the Centaurs only a few moments to dispense with her.
Harry’s desperation to be successful in his search for Sirius leads him to make several foolish errors and reveals the depth of Harry’s devotion. Harry never fully considers Hermione’s warning that Voldemort may be luring Harry into a trap, and he doesn’t stop to figure out why it’s so urgent for him to learn Occlumency. Having been through dangerous adventures before, Harry should, at the very least, suspect Occlumency is important for a reason and that this whole rescue of Sirius might be a hoax or a trap. Despite Harry’s past experiences, he allows himself to be driven not by logic but by fear. He believes Sirius is in grave, immediate danger, and this fear overshadows rational thought. Though Harry’s friends may realize they should stop and consider possibilities, they, too, are propelled forward by Harry’s urgency.