This is the game's penultimate stage, and the goal here is to find Zia. Defeat the Ura Warriors in the way of the game's final weapon, the Calamity Cannon; a fitting name for such a powerful yet chaotic ranged weapon. Test it out on the Security Turret that spawns and destroy the Conductors at each corner of the square on the floor. Destroy the obstacles in the path (this process moves quicker with the use of the Calamity Cannon) and continue forward. Past some more Ura Warriors and Security Turrets is a field of Stinkeyes. Defeat them and destroy the Conductors that surround them for extra Fragments. There's a fork here; the western path leads to more Fragments, a Health Tonic, and a Security Turret, while the eastern path leads forward.
Past more Security Turrets is the Arsenal; you may want to switch out the Calamity Cannon with a more stable weapon, as there are some tough battles to come. Destroy the Conductors ahead to open up a path to a battle with Rattle-tails. Take note that the southern path here is blocked; you can access it by firing at the Conductors behind the barrier with a ranged weapon. This gives you access to Something Burnt. Take the northern path to find an open area filled with various enemies (including a Stinkeye generator) and Conductors. Destroy everything in your path for maximum spoils, and take a branching path off to the east to find Something Foul.
At a fork, take the eastern path first to find Fragments and a Health Tonic. At the end of the western path, destroy the Conductors as usual to open up a new path. Defeat the enemies that spawn and fire at the Conductors across a gap in order to open the blocked path. Along this path, find a path to the west with a breakable barrier in the way. At the end of this path is Something Wrong, an upgrade material for the Calamity Cannon. Head north and destroy the Conductors, but don't move forward just yet; look to the left to find a memento, the Child's Drawing. Move forward to find Zia, who the Kid can interact with to return to the Bastion.