Note: If you so desire, it is entirely possible to avoid the confrontations in this section of the Fifth Ark by taking the detours on ledges along the walls. We'll assume that you decided to punch your way through all adversaries.
Pass through a couple of doors before the path opens out into another large area. Ahead some Phosphoric Ooze fight a Pulsework Knight so spring into action and get a preemptive strike on the unsuspecting enemies. Follow the waypoint marker down by somersaulting off the edge onto another path below.
Yet another three-way battle presents itself, this time with two Pulsework Knights and three Ooze. All that’s left to do here is run through the door to a Save Station and then pass through another door to the next area.