Trinity's third-level basement was almost like a different world on its own.
For a start, it was huge. An arena that was enough for friendly competition between espers of any type was set in the middle. Three sides of the arena were filled with doors leading to private training chambers of various sizes; from one that was enough for meditation, to one that could contain a destructive skill.
For that, the whole area was made of reinforced material that could withstand esper's mana, as well as fitted with barrier formations. Should a high emergency occur, the place would be the safest bunker in eastern Althrea. An arsenal, a medical center, and a logistic warehouse were there too, both to be accessed by the espers and for emergencies.