During the Brooklyn Naval shipyards level, you will have the option of entering the main building using a very large crane. Next to this crane is a heavy security bot patrolling, so it's very hard to miss. Use the crane to get onto the roof and then into a vent. Follow the vent until you reach a large cylindrical room with a large fan and a couple spider bots at the bottom. You need to reach the level where the spider bots are so take them out and then find a door that leads to a control room for the fan. Shut down the fan and the achievement is yours.