Stirring the Drone Nest

Head to the Grand Avenue area and take out all 12 militia drone tanks. Once done, head to the tunnel entrance and wait for Alfred to lower the door. Continue forth to find another closed gate. Use the power winch to pull the large ventilation fan above. Eject-glide to the hole and enter it.

Place the explosive gels on the boarded doorways and blast them. Remove the vent cover and go through the vent. Once you reach the other side, fire the Line Launcher to reach the other end of the room. Enter Detective Mode to see the button. Select your Remote Batarang and use it to push the power button in the enclosed room.

Once the gate to the right opens, use the Line Launcher again to conveniently get to the next ledge. Continue forth. Use the Line launcher once again to reach the ledge across the vent fan, then throw your Remote Batarang to the hole and steer it to hit the power button. Once the gate is opened, go through it once again using the Line Launcher.

Continue forth, turn to the right and you'll find a Riddler Trophy in the rubble.

Swing to the metal beam in the tunnel then continue hopping from beam to beam until you see a vent where you can enter near the locked gate. Continue to the control room and exit the grate. After the cutscene, you have to defeat a brute. Use beatdowns to take these large guys down.

More enemies will pour in. Use the environment takedowns, counterattacks, and any special combos/weapons you have to survive. Once you defeated most enemies, a drone tank will block the doorway and will start shooting inside. Go to its blind side to the right and finish off all enemies.

Now rewire the electric box to lower the Gate. Bring in the Batmobile and start destroying the tanks. Once done, continue to the next closed gate and open it. The enemies will attempt to escape, pursue them and eliminate the convoy's escorts using Immobilizer rounds. Continue chasing the APC then interrogate the driver of the APC. While interrogating him, press R2 to intimidate the poor ******* and make him spill his beans.

Head to the marked location in Grand Avenue to receive the Batmobile upgrade you selected from Lucius a while ago. You'll get the chance to try this new upgrade since the militia will send a bunch of tanks towards you.

After destroying all the tanks, Alfred will give you an update. You'll also get a new Mission (Armored and Dangerous)