So who is Ice Cream Maker Guy? According to the official Ice Cream Maker Guy website:
As Luke is battling Darth Vader in the Carbon Chamber and Lando, Leia, Chewbacca and C-3PO are running to escape from Bespin on the Millenium Falcon (they had just missed Boba Fett). Lando stops to announce: "This is Lando Calrissian, the Empire has taken control of the city. I advise everyone to leave the city before Imperial Troops arrive." They then take off down the hallway and Ice Cream Maker Guy rounds the corner running for his life.