Take your time to look around for ammo and armor once you're done killing enemy troops. Go to the stairs and read a new hint. Find a padlock on the gate [#133]. Fire one round at the padlock or use a melee hit to unlock access to a small storage. You will find a few interesting items here, including grenades and ammunition to most common weapons.
Now you'll have to make a few successful jumps, because it's the only way to reach the far side of the left platform. Start off by jumping onto a crate [#134]. Now you'll have to reach larger crates and finally the platform. Collect ammunition, use the ladder and proceed towards a new tunnel. You'll soon arrive at a very large warehouse.
Approach the barrier slowly and use the assault rifle to dispose of enemy troops from here. Naturally you'll be attacked by more soldiers when you reach the ground floor and this can only be done if you use the ladder. Check the side room [#135] and you'll find mines, armor, grenades and a new document - Lift problems. Go back to the main area of the warehouse.
Follow your current instructions and try using the control panel to activate a huge lift [#136]. Sadly the lift will stop after a short while and you'll receive further orders. Choose a combat shotgun from your inventory and locate all three valves. Don't approach them unless you're ready for a fight.
Each time you decide to get close to a valve you'll notice that several nearby tubes have been opened. This means you'll have to deal with Replica soldiers [#137]. Try using your reflex abilities to their full potential in order to prevent armor points losses. The main reason is that you'll need a lot of fresh armors soon. Approach each valve and hold the action key.