By creating sympathetic vibrations, Minstrel is capable of vibrating the Gotham City Stock Exchange. If he does not get his money, he's going to shake the stock exchange and all of Gotham City to the ground.
A stressed-out Chief O'Hara implies that Batman could be working in league with the Minstrel. He and Commissioner Gordon exchange heated words over the issue of Batman's loyalty.
Another culinary confinement for the caped crusaders!