I'm at the third hostage's location. The first parts of the puzzle were quite easy, but now I'm at the part where I need to use the Electrical Charger somehow (since there are three electromagnets).
I tried shooting the magnets in several combinations and nothing seems to happen. After messing around for a few minutes I decided to look the puzzle up on the internet. I found this guide: http://guides.gamepressure.com/batmanarkhamcity/guide.asp?ID=12645 It states (at the 11th row of images)
Prepare the Electrical Charge, as you will be using it to solve this puzzle. Start off by shooting at the left electromagnet #1 to move the steel platform left #2.
When I do that the steel box doesn't move to the left... Am I missing something here? Maybe something PS3 related?