You start out in a small entry lock of the ISV Kran. Walk through a door into the ship’s Aft Loading Station. Use the translator near the computer screens and bodies and collect the gear. and collect the gear.
Press the brightly lit computer screen, it lowers a lift in the middle of the loading area. Ride the lift upstairs to a small loop of the hallway. You have to fight a steady stream of Skaarj up here, keep fighting till no more appear. A ventilation grate in the floor will open, carefully jump down onto the metal bars, Follow the tunnel to a ledge overlooking the Ventilation Processing Mezzanine Ducts, collecting a RazorJack along the way, and drop down to the bridge.
On the bridge activate the computer screen, this releases the security locks to the warehouse. Shoot the light above the fan on the other end of the bridge and a grate will open to reveal an ASMD. Drop down to the lower ledge where you can go through mesh gates to return to the Aft Loading Station.
From there ride the lift upstairs and go through a newly opened door into the Warehouse area. To once side is an alcove with a GES BioRifle and ammo. Ride a lift on the other side to a platform, kill more Skaarj, and press the computer console. This drops a ramp, save the game and proceed up the ramp to the loft, a door locks you in as you enter.
A succession of Skaarj now break through ceiling ducts and attack, kill them all and the bars blocking the exit slide away. Press the computer console, then press the larger one. The translator will indicate that the security bars in the Warehouse have been disengaged. Go downstairs through a doorway that used to be barred for the next level.