After you regain control over Batman, bounce off the vantage point and glide towards the corrupt policemen under Batman, to attack them by surprise. Start the fight and remember, while fighting, to use the cape against the enemy with shield and preventing the policemen from firing at you. Deal with all of them and search out the door to the Maintenance Room. Approach Captain Gordon here to have a short talk with him.
[New character profile: Harvey Bullock]