Once you reach the part where Zuban dumps the hot soup on you (you can dodge it by clicking on the right side of the floor when he drops the pot). he will take off running out the door. Follow him through the alley, and you will encounter an old bum digging in the trash. Do not shoot him yet. Run up to the trash and dig in it. You will find a license plate. When you get it, the bum will start to walk away. Shoot him now. His body will fall to the floor, but he keeps on moving down the ally. If you follow him back the way you came, he will stand up for some reason and just keep on walking.