The Tunnel Club and the fridge
There are access tunnels and hallway tunnels, with rooms and labs and Pump Room's Lung-nexus off both sides, utility tunnels and storage tunnels and little blunt off-tunnels connecting tunnels to other tunnels. Maybe about sixteen different tunnels in all, in a shape that's more generally ovoid than anything else.
Context
The under-campus survey: E.T.A. sits on top of an ovoid loop of tunnels feeding back into each other. The school is built over a ring.