O Salgueiro Lutador era o método de guardar a passagem.
Quando o túnel foi originalmente construído, para infiltrar Lupin dentro e fora de Hogwarts, o Salgueiro Lutador foi colocado lá especificamente para proteger aquela passagem.
“I told you, months ago, that the Whomping Willow was planted the year I came to Hogwarts. The truth is that it was planted because I had come to Hogwarts. This house –’ Lupin looked miserably around the room, ‘– the tunnel that leads to it – they were built for my use. Once a month, I was smuggled out of the castle, into this place, to transform. The tree was placed at the tunnel mouth to stop anyone coming across me while I was dangerous.”
- Harry Potter and the Prisoner of Azkaban, Chapter 18 (Moony, Wormtail, Padfoot and Prongs)
Qualquer um vindo da Casa dos Gritos ainda encontraria o Salgueiro Lutador, então seria um guarda eficaz de qualquer um que tentasse entrar em Hogwarts também. A árvore pode bater bastante, e só há uma maneira de passar por ela - pressionando um nó específico no tronco. Mesmo que alguém saiba como parar a árvore, eles ainda teriam que fazê-lo fisicamente sem serem atingidos primeiro. Quando Harry e Hermione estavam perto, isso causou um grande dano a eles.
“Harry – we’ve got to go for help –’ Hermione cried; she was bleeding, too; the Willow had cut her across the shoulder. ‘No! That thing’s big enough to eat him, we haven’t got time –’
‘We’re never going to get through without help –’
Another branch whipped down at them, twigs clenched like knuckles.”
- Harry Potter and the Prisoner of Azkaban, Chapter 17 (Cat, Rat, and Dog)
Para uma pessoa parar, é provável que eles precisem de um longo bastão, já que a árvore provavelmente não os deixaria aproximar-se do nó.
“Sirius thought it would be – er – amusing, to tell Snape all he had to do was prod the knot on the tree-trunk with a long stick, and he’d be able to get in after me.”
- Harry Potter and the Prisoner of Azkaban, Chapter 18 (Moony, Wormtail, Padfoot and Prongs)
É possível que, se pensassem na passagem para a Casa dos Gritos, a equipe considerasse que o Salgueiro Lutador era suficiente para protegê-lo sozinho. Lupin era o único que sabia que Sirius era um animago, e ele mantinha segredo de todos, incluindo Dumbledore, então eles presumiam que seria um humano com quem eles lidariam, e não saberiam que ele poderia se transformar em um cão que era menor e mais baixo no chão.
Lupin não teria dito a Dumbledore que Sirius poderia passar por isso.
Lupin sabia que Sirius poderia passar pelo Salgueiro Lutador, mas ele estava mantendo muito em segredo de todos os outros que Sirius era um Animago e estava com ele todo mês. Ele pensou em dizer a Dumbledore depois de descobrir que Sirius escapou de Azkaban, mas ele nunca o fez.
“Lupin’s face had hardened, and there was self-disgust in his voice. ‘All this year, I have been battling with myself, wondering whether I should tell Dumbledore that Sirius was an Animagus. But I didn’t do it. Why? Because I was too cowardly. It would have meant admitting that I’d betrayed his trust while I was at school, admitting that I’d led others along with me … and Dumbledore’s trust has meant everything to me. He let me into Hogwarts as a boy, and he gave me a job, when I have been shunned all my adult life, unable to find paid work because of what I am. And so I convinced myself that Sirius was getting into the school using Dark Arts he learnt from Voldemort, that being an Animagus had nothing to do with it … so, in a way, Snape’s been right about me all along.”
- Harry Potter and the Prisoner of Azkaban, Chapter 18 (Moony, Wormtail, Padfoot and Prongs)
Ele também não teria dito a Dumbledore que Sirius sabia como passar pelo Salgueiro Lutador, já que isso revelaria que ele estava quebrando as regras.
“I sometimes felt guilty about betraying Dumbledore’s trust, of course … he had admitted me to Hogwarts when no other Headmaster would have done so, and he had no idea I was breaking the rules he had set down for my own and others’ safety. He never knew I had led three fellow students into becoming Animagi illegally.”
- Harry Potter and the Prisoner of Azkaban, Chapter 18 (Moony, Wormtail, Padfoot and Prongs)
Lupin não teria dito a Dumbledore que Sirius poderia passar pelo Salgueiro Lutador, porque explicar isso também significaria ter que admitir que ele traiu a confiança de Dumbledore e quebrou as regras.