Why..

“This whole thing happened because you wouldn't face up to Gideon dying.' he said, which was a stab as precise as any Nonius had managed. 'I don't blame you. But where would you be, right now, if you'd said: She is dead? You're keeping her things like a lover keeping old notes, but with her death, the stuff that made her Gideon was destroyed. That's how Lyctorhood works, isn't it? She died. She can't come back, even if you keep her stuffed away in a drawer you can't look at. You're not waiting for her resurrection; you've made yourself her mausoleum.”
― Tamsyn Muir, Harrow the Ninth