So, after playing this game and actually escaping (w/o sound on) I actually have to say this is what I'm looking for in concept for a stealth survival game (w/ vore).
This might be difficult to implement but it might help the player if you could somehow hide under the teacher's desk or a closet so if chases end up in the classroom and our friend Bella strolls in, there's a chance to escape (would also totally wouldn't complain if there's a chance Bella would start checking these spots if you abuse these methods).