Snape vet för ett faktum att Voldemort inte blir död.
‘Tell him that on the night Lord Voldemort tried to kill him, when Lily cast her own life between them as a shield, the Killing Curse rebounded upon Lord Voldemort, and a fragment of Voldemort’s soul was blasted apart from the whole, and latched itself on to the only living soul left in that collapsing building. Part of Lord Voldemort lives inside Harry, and it is that which gives him the power of speech with snakes, and a connection with Lord Voldemort’s mind that he has never understood. And while that fragment of soul, unmissed by Voldemort, remains attached to, and protected by Harry, Lord Voldemort cannot die.’ Harry seemed to be watching the two men from one end of a long tunnel, they were so far away from him, their voices echoing strangely in his ears.
‘So the boy … the boy must die?’ asked Snape, quite calmly.
‘And Voldemort himself must do it, Severus. That is essential.’ -Deathly Hallows
Så han vet att allt han gör kommer bara att sakta ner Voldemort.
Nu tidigare tog det Voldemort omkring 12 år innan han återfick sin kropp, men vi vet att med någon för att hjälpa honom att skapa en ny kropp är det enkelt.
Death Eaters gick aldrig för att hjälpa honom, och alla trodde honom döda första gången. Men nu står majoriteten av dödsätarna här och ser honom komma tillbaka från de döda, bevittna Voldemort, förklara hur han tar tillbaka honom igen på kyrkogården.‘I remember only forcing myself, sleeplessly, endlessly, second by second, to exist ... I settled in a faraway place, in a forest, and I waited ... surely, one of my faithful Death Eaters would try and find me ... one of them would come and per- form the magic I could not, to restore me to a body ... but I waited in vain ...’
But I was willing to embrace mortal life again, before chasing immortal. I set my sights lower ... I would set- tle for my old body back again, and my old strength.
‘I knew that to achieve this – it is an old piece of Dark Magic, the potion that revived me tonight – I would need three powerful ingredients. Well, one of them was already at hand, was it not, Wormtail? Flesh given by a servant ... ‘My father’s bone, naturally, meant that we would have to come here, where he was buried. But the blood of a foe ... Wormtail would have had me use any wizard, would you not, Wormtail? Any wizard who had hated me ... as so many of them still do. But I knew the one I must use, if I was to rise again, more powerful than I had been when I had fallen. I wanted Harry Potter’s blood. I wanted the blood of the one who had stripped me of power thirteen years ago, for the lin- gering protection his mother once gave him, would then reside in my veins, too ... -Goblet of fire
Så Snape som dödar Voldemort när som helst från bok 4, köper högst trioen, men det tar lång tid att brygga potionen till en kostnad av potentiellt sitt liv och förlora möjligheten att spionera på sina planer, såväl som potentiellt krossade Dumbledores vaga plan han delades där Voldemort måste döda Harry.
Att döda Voldemort och sedan få Voldemort att använda någon annans blod för att skapa en ny (3: e) kropp skulle förlora skyddet Lily, förutsatt att han levde i Harry's blod, det skydd som hållit Harry vid liv i Förbjudna Skogen >
"Precisely!" said Dumbledore. "He took your blood and rebuilt his living body with it! Your blood in his veins, Harry, Lily's protection inside both of you! He tethered you to life while he lives!" -Deathly Hollows
Denna tätning av livet mellan de två är väsentlig för att Harry ska kunna få Voldemort att döda hans själs del inuti Harry, utan att Harry också dör.
Snape är inte medveten om allt som händer, med Harry och horcruxerna, inte heller sambandet mellan harry och voldemort på grund av lilysoffret. Men Snape litar på Dumbledore helt och Dumbledore har gjort det klart att Voldemort har att döda Harry.