Arc didn't know that this small movement was just the calm before the storm, as small stones falling slowly started to change into big rocks.
These falling rocks were part of the wall of this maze which was falling now for some reason.
Arc quickly jumped back or his Skely body would be crushed under it.
The reason for this wall falling slowly was revealed when he saw an Ape punching the wall when things got out of his view. This Ape was in a sort of maddened state and was solely focused on destroying the walls in his surroundings that were stopping him.
Arc decided to run away from this danger because something was telling him that he could not take on this guy because this monster was able to destroy the walls that he could not destroy.
