How do I get to Riddler's second hostage in the Enigma Conundrum side mission?
I've rescued Riddler's first hostage from the courthouse, and gone to the location of the second hostage, outside the Black Canary. However, I've search all over the building and can't find any doors or other entrances. How do I get in the building with the second hostage? Or do I have to go somewhere else?