He'd gone to the roof to look for clues to the Joker's whereabouts. Any trace of material that he could trace back to its origins, any pricetag, even an empty bottle that he could track back to the Wal*Mart he bought it at. He'd gone under the impression that the Joker would have long cleared the scene, what with the police responding to the nearby Gotham Times building to rescue anyone trapped inside and clear the rubble. So, when he came creeping up the back side of the roof in full bat-gear and took his dear sweet time rolling his grapling hook back up and putting it away, he didn't expect to turn and see the Joker still sitting there, waiting, glasgow grin glowing against a background of dancing flames. Sickening.

It took him a half a second to gather his wits about him. Too long. He was running across the roof as soon as he did, though, which made up for the time. His mind blanked on whatever evidence could be ruined in the process of throwing the villain around. He was determined. Fixated. Obsessed. Focusing on only one thing: Joker. Get the Joker.