Wu Siduo explained as she walked, "The sanctuary is situated 300 meters beneath the ground, and it was designed specifically to be able to defend against powerful soul weapons. It was completed 3,000 years ago, and at around 200 meters beneath the ground, is where the first layer of concrete mixed with alloys lies. There are several dozens of these layers, so even the explosion of a Godslayer missile won't be able to affect the interior of the sanctuary. The sanctuary is actually large enough to house more people, but the attack was too abrupt, and without the sacrifice of the teachers, the protective barrier wouldn't have lasted until all of us could enter the sanctuary.

"The elevator leading to the sanctuary also has a limited capacity, and that was why we suffered so many deaths. Following the explosion, we had no idea what the situation was like on the surface, and it was Teacher Wu who used the facilities inside...