Bella does not try to have a full-on conversation with Marcy et al while in the middle of maleficaria studies. Instead she nods politely, sits down without making a huge fuss about it because while New Orleans is small it's at least a real enclave and she doesn't look like a parasite waiting to happen so she needn't worry too much about friendly overtures seeming loaded, and takes notes on amphisbaena perfectly studiously for an hour and a half. (There isn't actually an hour and a half's worth of material on amphisbaena if you're a fast reader and notetaker and have an eidetic memory for the day, so she attempts to temporarily trade textbooks with the nearest Sino so she can do it over again in Chinese, but communicating this concept in gestures ultimately fails and she isn't willing to try suggesting it out loud while other people are still trying to concentrate. Maybe she will arrange a textbook swap plan with Wei Wuxian later, he seems quick.) She goes over her schedule for the rest of the period instead, and then when the bell rings she taps Marcy on the shoulder before the Bostonians can peel off. "I met an interesting alchemist at breakfast. Makes eidetic memory potions."