The walls are designed according to franchise, as well as the flooring. The gravity is normal here... Half-surprisingly, it's the quietest floor.
Quinary Hall is the fifth floor of The Place. Here, characters can transfer from one place to another. This hallway contains the Undertale(E1), Shall We Date?: Wizardess Heart+(E2), and El Tigre(E3) franchises.

This hallway also has a cafeteria and library... That might half-explain why it's so quiet, actually.