what if they're both pouring through the thesaurus. tbh the ninth probably has more than one but it's funnier to me if they're somehow accidentally alternating studying from the only one available in the library, unaware of the other, except when it's not there which is clearly a DELIBERATE ACT OF PSYCHOLOGICAL WARFARE (it's not, Ortus has it. they would know this if either of them used the sign out sheet.)
this is incredibly funny & i accept it as canon immediately