Someone Always Benefits From The Others Loss [1]
The labyrinth's third floor and the ground shook intensely as if an earthquake had occurred. Dust and rocks fell from the ceiling and the dead bodies of the monsters vibrated as they rolled in the pool of their own blood.
The entrance gate of this floor—one from where Zero and the other came inside, got closed off as a big slab of hard rock slid down its corners and stood like a wall.
Spene, Xara, and Favian, of course, saw this and panicked. This meant only one thing and that was they can't go back now. One other gate that was on the opposite side from the entrance gate had also closed, so it was probably the gate to the next floor.
This wasn't a unique situation, and everyone from the little bit of experience they had in the labyrinths knew that if a situation like this occurred then the only way to open the doors was by killing all the monsters on the floor they were currently in.