"It's in the Catacombs, by the emergency wands, but you can't use them-" I know I can't use magic there; but at least I have Severus" skullduggery. And a few of my own tricks up my sleeve, like making these corpses believable enough to be us. The Slytherin put a glamour on the exposed wrist to mark it like her wife's, and quickly turned the wand upon her son.