Back with Sazh and Vanille, your first task is to create the Undermine Paradigm (RAV and SAB) which allows a build and maintain strategy for Chain Gauges; Pulsework Soldiers are especially vulnerable to it.
A device that activates the bridge can be seen just ahead so interact with that. During this section, be very aware of Bombs. Veterans of Final Fantasy should know about their devastating Self Destruct ability which they like to use just as their health gets low or after a certain amount of time. Battles with several enemies and Bombs should see you focus on those first or your leader can be obliterated without a second thought.
Before you charge forwards, turn around, run south and jump all the way up to the top (while ignoring Vanille’s remarks) to grab a Phoenix Down . Return to ground level and proceed onwards, taking down the Bomb as you pass. Two more can be found at the bottom of the staircase along with another device that draws a platform towards you. Cross over, dismantle the Pulsework Soldier then keep running until you see a group of Bombs with a Soldier. To the right, on a ledge, is an Auric Armlet .
Move past the Save Station, around the corner, then set upon the little penguin-type enemies. Gremlins are fairly powerful magic users but have low HP and aren’t a significant threat unless in large numbers. A trio of them guard another Ember Ring so extricate them from it and carry on making progress towards your goal.
When you reach the area with four devices, turn right immediately as you come down the hill and collect another Phoenix Down then afterwards, jump up to reach the first device. Remove the enemies first then access it to power up the first pillar. Turn north towards the next one which is guarded by two Pulsework Soldiers. No problem. Power up this one too.
Cross over to the other side where the next one can be found. A Bomb and Soldier patrol here. Finally, move south to another guarded by two Bombs. The central pillar will be fully operational now though it releases a large group of enemies as a consequence. To the right of the Save Station is a Fortisol which you should collect before turning south and running all the way round to a new area.
Skirt the debris and press the control panel for the elevator just right of the path. This takes you to up to another area with more enemies and a switch that creates a staircase. Take the stairs and turn right to battle more Bombs and activate another set of stairs. Follow the new path to a dead-end home to a large group of Bombs and Pulsework Soldiers. Your reward is 8x Iron Shells from a Treasure Sphere. Hmm, was it worth it?
Head all the way back to the fork and go straight on this time (as opposed to right) down to yet another device. It’s a good job Sazh is pretty handy with electrical things. This particular switch builds a path to some Soldiers and a Sphere ( 6x Vibrant Ooze ) tucked away in a container. Return back to the path and head in the direction of the waypoint marker and then use the elevator to get back to the previous area.
All the enemies will have respawned so battle them again if you wish but otherwise, follow the marker and destroy the enemies that block the path. Inside the cave you can find 300 Gil . A series of lengthy cutscenes ends this section.