Continue downstairs and take out the enemies in the next room. Open the door to the galley and take cover. Clear the room then you'll have to pull the switches of the gas lines. There's a COG tag in this area, located in empty storage room in the corner.
After activating the first gas line, more locust reinforcements will storm the room. Kill them all then activate the last two remaining gas lines.
In the next sequence, you'll be ziplining down the building. Take out the gondolas along the way using your pistol and the chapter will be complete.