Now head back inside. You need to make a path for the Batmobile so you have to clear the platform above the crane to access the controls. After clearing the initial wave of guards, you have to deal with some sort of elite melee soldiers. Defeat them and control the crane. Position the crane so you can use it as a ramp. Cross the gap to reach the next area with the Batmobile.
Now you have to clear the next courtyard of enemy tank drones. Aim for their turrets and use the thrust-evade to quickly get out of their line of sight. Once the courtyard is cleared, find the gas valve under the Loading Dock room and pull it using the power winch.
Clear the Loading Dock room and place some explosive gel on the wall beside the pipe. Continue forth and find the next deceased hostage. Continue forth and use the explosive gel on the floor. Get to a safe distance and blow it up.
Now drop down and rewire the electric box nearby. This will open a window which will allow your Batmobile to fire its power winch. Now blow the next wall and pull the valve on the pipe.
Once done, turn to the left and you'll find one of the workers again. Continue forth and rewire the electric box again near the hatch to open it. Control the Batmobile once again and blow up the cracked wall. Attach the power winch and pull the elevator as far as the Batmobile can. Release the remote control, have Batman crawl inside the elevator through the opening in front of the Batmobile. Control the Batmobile again and have it lower the elevator to the very bottom.
You'll find the hostage inside and a lot of unarmed guards. Use your grappling hook to access the vent on the ceiling and make your way through until you find another grate that you can remove. Head further inside until you can get into a vantage point where you can trigger a Fear Multi-takedown. By default, you can only take out three of them via Fear and the remaining guards, you have to dispatch them using conventional melee combat.
After taking out the guards, free the hostage. Head back to the elevator and take control of the Batmobile again to pull it up. Exit the elevator and another scene will trigger. Now you'll have to deal with another wave of tank drones and an attack helicopter.
Take out the drones first then deal with the chopper. Use the thrust-evade to avoid its missile volley then make sure to fire the vulcan fire whenever your main gun is reloading. Later on the chopper will fire homing missiles. Use your vulcan fire to destroy them before they completely lock on to the Batmobile.
After defeating chopper, park the Batmobile on the lift and disembark. Activate the elevator controls nearby to raise the lift and allow the Batmobile to cross. Now deliver the hostage to the police and head back inside the compound once more.