Now you need to complete a short scene while controlling Gordon. Start walking towards the elevator. When you reach it, interact with it and wait until you pass the verification process. Enter the elevator and press the red button to get to a new location.
Enter the large hall and start examining the cells located on your both sides. Talk to the prisoners. Batman will soon appear in this location and you will watch a cut-scene. When it's over, you will go back to what you were doing previously.