Marian has been kind of stewing in the back of her mind ALL AFTERNOON about the horribly traumatized illiterate maleficer kid who she gave either ketamine or MDMA (who knows which? she can probably make a guess by asking him about the effects but it's not like she's an expert on either.) 

After dinner, she finally gets up the courage to leave her warded infirmary again. She managed to sweet-talk the void wall into giving her two entire 1L bottles of Pedialyte; literally the only thing she can remember about this is that they had a teenage patient once who took MDMA for a rave, stayed up all night dancing, and then collapsed of dehydration. 

Knife at the ready, she asks various students until she's able to learn from the Shanghai table that the creepy Mandarin-speaking maleficer kid is stalking some other girl. Lily? And someone saw them in the library earlier. 

Well, if Wen Qing is willing to accompany her, they have some MEDICAL FOLLOWUP to do. Which is an important component of nursing care that Wen Qing also needs to be learning about, so. 

Carrying her knife in one hand, with a bottle of Pedialyte awkwardly shoved into both her front pockets, she treks library-ward with Wen Qing.