Destroying the fifth container
The fifth container can be found inside the Museum, in the War Room located in the south part of the building #1. The Museum entrance is of course guarded by inmates #2. It's also worth noticing that you can fully explore this building only after completing Disable Penguin's Final Communications Disruptor underground.
Your goal is reaching The Torture Chamber located in the middle part of the Museum. If you come here before defeating Penguin (Rescue remaining undercover GCPD officers in the Museum main mission), the majority of the room will be covered in ice #1, forcing you to carefully plan your moves. If you have already defeated Penguin, the whole area will be flooded #2 and you will have to constantly use the floating platforms or make use of the Freeze Blast (ice floes).
Regardless of the scenario, you have to head to the south part of the Torture Chamber #1. Swim or walk there and afterwards use the Grapnel Gun to reach the upper shelf #2.
If you have defeated Penguin, you will be able to revisit the War Room without any problems. Otherwise, you will have to solve a puzzle. Turn on the Detective Mode and note the laser barrier here. Equip the Cryptographic Sequencer and use it on the nearby control panel #1. In this case the password is FOSSIL #2.
Now you can attack the inmates who have been laughing of you until now. Look out for the armoured enemy #1. As a reminder, it's best to first stun them (B) and afterwards use Beat Down (by rapidly pressing X). regardless of whether you had to fight here or not, choose the door leading to the War Room #2.
Head west. Upon reaching the partially closed gate #1 start running and slide underneath it. If you have already fought here, you will be able to head north-west at once. Otherwise you will have to blow up the wall here #2. It of course means having to use the Explosive Gel.
Detonating it will lead to a fight with a few Thugs, including a mini-boss Abramovici #2. The enemy is very similar to Mr. Hammer that you've already fought during Break into Joker's office in the Loading Bay. Therefore you have to avoid his standard hits and charged jumps. In the first part of the battle it's of course worth to take care of the normal enemies #2, avoiding the boss' attacks.
Keep fighting until Abramovici is the last enemy still standing and use the Electrical Charge to temporarily stun him #1 and afterwards start rhythmically pressing X to attack #2. One such series should do the job.
Regardless of whether you have fought or not, you have to use the north-west passage #1. Afterwards turn south and eventually you should reach the container #2. Spray the Explosive Gel on it and detonate.
Destroying the sixth container
The last, sixth container can be found in the Wonder Tower Foundation #1. If you have already finished the story mode, you should have an idea of how to get there. Otherwise, it would be good to wait until you receive the Follow assassin using tracker device to locate Ra's al Ghul objective and reach the Subway Station - which you have already approached while looking for the fourth container #2 - as part of it.
If there are thugs at the station, you will have to take care of them. Otherwise you can start looking for an interactive door in the northern part of the station #1. After going through a narrow corridor you will reach a spot where you will have the use the Line Launcher #2. Aim at the distant wall and shoot the line.
After reaching the new ledge, look up and use the Grapnel Gun to reach the upper level #1. Open the door leading to the Collapsed Street. Head north and afterwards turn west, stopping by another pit #2.
Prepare the Line Launcher and shoot at the opposite wall #1. If there are any enemies in the area, I'd suggest attacking them by surprise. In order to do that you would have to change direction while on the line. Hold down the left trigger and wait until you are nearby the enemy room #2. Attack them and be careful, as some of them might be equipped with firearms and use armour.
Regardless of whether you had to fight or not, choose the northern door leading to the Wonder Tower Foundation #1. There's a high probability of coming across enemy units here as well #2. If it's your first visit here, I'd suggest checking out the Follow assassin using tracker device to locate Ra's al Ghul walkthrough.
If you have already been here before, you won't have to worry about keeping the hostage alive. Nevertheless it's worth to carefully plan your actions and use the vantage points #1, ventilation shafts and other environment elements to your advantage. After clearing the room, examine its southern part to find the container #2. Spray the Explosive Gel and detonate it.
Return to Bane
As you have destroyed all the containers, you can now return to Bane. As a reminder, he can be found in the Krank Co. Toys building in the eastern part of the city #1. Unfortunately, enemies have appeared by the entrance in the meantime #2 and additionally they're equipped with firearms. Therefore you should try and take out at least one of them silently.
Enter the building and head to the main room to talk with Bane #1. You will be interrupted by the arrival of TYGER guards #2.
Note that in this fight, Bane will be your ally. What's more, there aren't any elite units among the enemies, so winning shouldn't be hard #1. Try to keep your distance from him, as otherwise he might accidentally hit you. Afterwards watch a short cutscene, showing Bane's failed attempt to trick Batman #2.
Go inside the room in which Bane stored the six containers he has found #1 and prepare the Explosive Gel. Plant two charges, at best on both middle containers on both sides of the room. Step away and detonate the charges #2. The quest will completed only if you manage to destroy all of the containers. Before getting out of the building you can speak with Bane again, though it's completely optional.