McGonagall tells Ron to come too and leads the boys to Dumbledore's office. Harry tries not to panic as he tells Dumbledore what he saw. He also tries to curb his irritation with Dumbledore, as Dumbledore still won't look directly at him. When Dumbledore learns that Harry saw this happen from the snake's perspective, he calls on two sleeping headmasters' portraits and sends them to raise the alarm where Mr. Weasley is. He then sends Fawkes away, saying they'll need "a warning." Dumbledore pulls out one of his small silver instruments and when he taps it, its puffs of steam turn into a snake and then into two snakes.
Dumbledore's unwillingness to look at Harry or tell Harry anything useful about what just happened means that Harry feels ignored and like he's just a messenger, not someone experiencing an identity crisis and a terrifying interlude as a violent snake. Harry also doesn't understand why Dumbledore is ignoring him. Though he'll later learn that Dumbledore is doing this for Harry's own good, it becomes clear here that Dumbledore's intentions don't make Harry feel any better right now.
One of the headmasters returns and says that people just took Mr. Weasley to St. Mungo's hospital. Dumbledore then sends McGonagall to get the other Weasley children. He turns an old kettle into a Portkey, wakes the portrait of a man named Phineas, and sends him to his portrait in Grimmauld Place to alert Sirius that Harry and the Weasley children will be there soon. Ginny, Fred, and George arrive, and Dumbledore explains that Mr. Weasley was injured in his work for the Order. When one of Fawkes's feathers drops into the room, Dumbledore instructs them to touch the kettle. As Harry looks at Dumbledore, they finally lock eyes and he suddenly feels searing hatred and a desire to bite him. The sensation disappears as the Portkey carries Harry away.
Dumbledore confirms that Mr. Weasley was doing work for the Order when the snake attacked him—and Mr. Weasley was asleep. This suggests that even though whatever Mr. Weasley is doing is certainly important and worthwhile, that doesn't mean it's not boring enough to fall asleep on the job. The frightening impulse Harry feels when he finally meets Dumbledore’s eyes suggests a reason for why Dumbledore has been purposefully ignoring him, but Harry doesn’t get any more information about this and so is left feeling even more alone.
Harry falls to his knees as he arrives in the kitchen of Grimmauld Place. Sirius angrily shouts Kreacher to leave and approaches his guests with concern. Harry tells everyone what he saw, but he tells the story as though he saw it happen from the sidelines, not from the snake's perspective. Fred, George, and Ginny insist they need to go to St. Mungo's immediately, but Sirius insists they can't—Mrs. Weasley doesn't know yet, it would jeopardize the Order, and it would raise Ministry suspicions about Harry if they knew he was having visions. He says that Mr. Weasley knew what he was getting into when he joined the Order, but Fred shouts that it's easy for Sirius to say that, since he's not risking his life. Sirius composes himself, summons butterbeer, and insists they stay.
In this situation, Sirius has to act as a parent figure and impress upon the Weasley children that the most important thing right now is keeping the Order a secret. Because Sirius has acted more as a peer than an adult authority figure, this is more difficult for him to do—and Fred feels able to fire back with his comment that Sirius isn't doing anything meaningful. His words strike at Sirius’s insecurities about being stuck inside the house and not really being useful to anyone. This is also later revealed to be the moment Kreacher first leaves the house, taking Sirius’s command to get out literally.
Harry feels incredibly guilty as they all sit together in silence. He reasons that though he made sure Mr. Weasley was found, they'd all be asleep if he hadn't had the vision. He tries to tell himself that he didn't actually attack Mr. Weasley, but he's afraid of what happened in Dumbledore's office too. A while later, one of Fawkes's feathers appears. It's a note from Mrs. Weasley saying that Mr. Weasley is alive and to stay put. Everyone remains at the kitchen table until Mrs. Weasley walks in at a little after five in the morning. She says that Mr. Weasley is going to be okay. They can visit him later.
Again, Harry's guilt in this situation stems from the fact that Dumbledore chose not to sit Harry down and tell Harry what's actually going on with his visions and dreams. Doing so would reveal to Harry that he's not actually doing anything wrong; he has a connection with Voldemort that sometimes causes him to feel what Voldemort is feeling.
Sirius and Harry busy themselves making breakfast and Harry dreads the moment that Mrs. Weasley asks him to recount his vision. However, when she enters she grips him in a hug and thanks him. She then turns to Sirius and asks if they can stay at the house through Christmas, which seems to thrill Sirius. Harry then calls Sirius aside and privately tells him the truth about his vision of being the snake. Sirius believes that Dumbledore would've said something if he were worried, and he also seems unconcerned about Harry's brief desire to attack Dumbledore. Sirius sends Harry to bed after breakfast, insisting that he's just in shock.
Sirius's lack of concern makes Harry feel even worse, which shows again that Sirius's intention doesn't matter (as he's probably trying to make Harry stop worrying about what happened so he can get some rest); the fact remains that it makes Harry feel alone and afraid of his own mind. Harry thus continues to question his experiences, his sanity, and whether he's even in control of his own mind—all things that make him vulnerable to manipulation.
Harry goes to bed, but he stays awake, as he's afraid he'll attack someone else in his sleep. Tonks, Moody, and the children's trunks arrive around lunchtime and after they change into Muggle clothes, they all head for St. Mungo's. Moody stops the group in front of a rundown department store, and they all walk through the window glass. Harry finds himself in a waiting room and follows Mrs. Weasley to Mr. Weasley's ward, the "dangerous" ward for "serious bites." Harry tries to hang back with Tonks and Moody, but Mrs. Weasley pulls him into the room along with the family.
The fact that Harry is afraid of attacking someone else speaks to how little he knows about what's going on and how his visions function. His fear is valid given what he knows, but he's not the one attacking people and isn't at all dangerous to his friends. This sense of guilt makes Harry want to withdraw and not be a part of the family when they visit Mr. Weasley.
Mr. Weasley is cheerful and says he feels fine, but he bleeds profusely every time they take the bandages off. He motions to another man in the ward who was bitten by a werewolf. This concerns Mrs. Weasley, who fears for their safety, but Mr. Weasley reminds her that it's two weeks until the full moon. He says he mentioned that he knows a werewolf who lives a normal life, but the bitten man wasn't interested in hearing this. Fred and George try to ask what happened to Mr. Weasley. He refuses to say, and instead offers that they discovered that a man named Willy Widdershins was behind the regurgitating toilets, but he wasn't convicted.
It's telling that Mrs. Weasley is so concerned about a werewolf in a monitored, contained hospital setting when she sits with the werewolf Lupin at every Order meeting. This suggests that a fear of werewolves is something that runs deep in society, and even a wholly positive character like Mrs. Weasley can share these troubling views.
Mrs. Weasley herds the children out and lets Tonks and Moody in, closing the door behind them. Fred and George find Extendable Ears and offer one to Harry. The adults discuss that nobody could find the snake and that Dumbledore has been acting like he expected Harry to see something like this. Moody growls that Voldemort is possessing Harry, and when he hears that, Harry yanks the Extendable Ear out of his own.
While learning that Voldemort might be possessing him is bad enough, another devastating piece of information for Harry is that Dumbledore has been expecting something like this, but hasn't let Harry in on that detail. This makes Harry feel even more isolated and like the adults he trusts won't look out for him, as he should be able to expect them to.