A principal razão pela qual Voldemort esperava que Harry viesse ao Ministério era que Harry tinha uma queda por heroísmo. Como Lucius Malfoy disse a Bellatrix durante o confronto:
"Oh, you don't know Potter as I do, Bellatrix,” said Malfoy softly. "He has a great weakness for heroics; the Dark Lord understands this about him.
Hermione também percebeu isso:
“Okay,” she said, looking frightened yet determined, “I've just got to say this...”
"What?”
“You... This isn't a criticism, Harry! But you do... sort of... I mean — don't you think you've got a bit of a — a — saving-people-thing?” she said.
He glared at her. “And what’s that supposed to mean, a ‘saving-people-thing’?”
“Well... you...” She looked more apprehensive than ever. “I mean... last year, for instance... in the lake... during the Tournament... you shouldn’t have... I mean, you didn’t need to save that little Delacour girl... You got a bit... carried away...”
A wave of hot, prickly anger swept Harry’s body — how could she remind him of that blunder now?
“... I mean, it was really great of you and everything,” said Hermione quickly, looking positively petrified at the look on Harry’s face. “Everyone thought it was a wonderful thing to do —”
“That’s funny,” said Harry in a trembling voice, “because I definitely remember Ron saying I’d wasted time acting the hero... Is that what you think this is? You reckon I want to act the hero again?”
“No, no, no!” said Hermione, looking aghast. “That’s not what I mean at all!”
“Well, spit out what you’ve got to say, because we’re wasting time here!” Harry shouted.
“I’m trying to say — Voldemort knows you, Harry! He took Ginny down into the Chamber of Secrets to lure you there, it’s the kind of thing he does, he knows you’re the — the sort of person who’d go to Sirius’s aid! What if he’s just trying to get you into the Department of Myst — ?”
Ele sabia que, baseado em informações de Kreacher, o sequestro de Sirius seria a coisa que desencadearia particularmente o heroísmo de Harry:
“Oh yes,” said Dumbledore. “You see, Kreacher was not able to betray us totally. He is not Secret-Keeper for the Order, he could not give the Malfoys our whereabouts or tell them any of the Order’s confidential plans that he had been forbidden to reveal. He was bound by the enchantments of his kind, which is to say that he could not disobey a direct order from his master, Sirius. But he gave Narcissa information of the sort that is very valuable to Voldemort, yet must have seemed much too trivial for Sirius to think of banning him from repeating it.”
“Like what?” said Harry.
“Like the fact that the person Sirius cared most about in the world was you,” said Dumbledore quietly. “Like the fact that you were coming to regard Sirius as a mixture of father and brother. Voldemort knew already, of course, that Sirius was in the Order, that you knew where he was — but Kreacher’s information made him realize that the one person whom you would go to any lengths to rescue was Sirius Black.”
É verdade que os membros da Ordem estavam por perto, Harry provavelmente não teria corrido para o Ministério sozinho, mas Voldemort não deu a Harry a visão quando outros membros da Ordem estavam por perto. Ele sabia que Dumbledore havia partido de Hogwarts e presumivelmente sabia que McGonagall também tinha ido embora. E ele especificamente se certificou de que ninguém da Ordem estivesse por perto para receber a comunicação de Harry para o Largo Grimmauld, como Dumbledore disse a Harry depois:
“The Malfoys — undoubtedly on Voldemort’s instructions — had told him he must find a way of keeping Sirius out of the way once you had seen the vision of Sirius being tortured. Then, if you decided to check whether Sirius was at home or not, Kreacher would be able to pretend he was not. Kreacher injured Buckbeak the hippogriff yesterday, and at the moment when you made your appearance in the fire, Sirius was upstairs trying to tend to him.”
Além disso, Voldemort pode ter confiado nas escapadas passadas de Harty. Notavelmente, Harry foi atrás da Pedra Filosofal e da Câmara Secreta sem obter ajuda de nenhum professor ( Lockhart não conta ), então Voldemort pode ter esperado que ele fizesse o mesmo neste caso também.
Quanto a como Voldemort esperava que Harry também chegasse ao Ministério, ele provavelmente supôs que Harry iria voar até lá por vassoura.
Em suma, isso pode ter sido um plano decente ( especialmente comparado a outros planos Voldemortianos ), e de fato funcionou no final.