Ace Chemicals 3

Blow up the wall of the main building then exit the Batmobile. Get on top of the crane controls above and position the crane so the Batmobile can use it as a ramp again. Once inside, follow the road and take out the bots along the way.

Once you've reached another gate, exit the Batmobile and use the grapple hook to reach the ledge above. The best way to quickly take out these two guards is via Fear Multi-takedown. Swing to the pipe above the sentry then you can enter through one of the vents on both sides of the room. This will take you under the floor where you can get beneath the guards and take them out. Quickly use your grappling hook to get out of the sentry's detection range and get near the sentry until you get a prompt to destroy it. Rewire the electric box to open the gate and ride your tank again.

When you reach another gate, climb up the ledge and drop down near the electric box below without making a scene. After rewiring and opening the gate, the enemies will be alerted to ride your vehicle again and start shooting at the spooked enemies. Disembark the Batmobile and finish off the remaining enemies on foot. Make use of the Batmobile and environment takedown options in this area.

Once clear, enter the batmobile again and use the eject-glide function to get over the gate of the mixing chamber. Silently take down one of the guards and destroy the sentries if you want. Now you have to clear the mixing chamber and take down all the guards to prevent them from loading the chemicals.

Once cleared, enter the main chamber to find Scarecrow. After the scene, access the terminal to prepare the neutralizing agent. The four tubes containing the neutralizing agents must be carried to the other holes where you can insert them. Take note that these chemicals are highly volatile so you have to keep an eye on the color indicators while moving it. You also have to be very careful when inserting them in to the holes. After getting the fourth tube, a cutscene will trigger.

You'll now be controlling Commissioner Gordon. Head inside the elevator and operate it. Speak to all the prisoners until a cutscene triggers.

After the scene, switch control to your Batmobile and use the power winch to pull the side of the chamber. Ride the Batmobile and escape the place.