“Min,” Schmendrick cried, looking at the mirror in horror.
Ahn explained for Dame Catherine’s benefit. “When a container is not made unique to the function it is in, as min was not, it is sometimes exposed to whatever larger incantation that function is in, or even the larger context in which the spell is cast. All spells cast within this house run within the context of the house’s master spell. Schmendrick’s timer spell also uses a non-unique container called ‘min’ to hold the number of minutes it should run, like the safe retreat spell used a non-unique container called ‘min’ to hold the number of berries.”