Physical Danger
You're constantly switching between sitting and standing while working at a mall kiosk, so the physical danger is mostly concentrated on the back and knees. The stools they usually provide are far from comfortable, so issues with your lower back and legs may pop up. Also, the amount of fast food from the mall cafeteria you consume may increase. Watch your carbs and sodium intake (and your weight).
Otherwise, you're looking at more distant and unlikely physical dangers, such as robbery, or overly aggressive customers. There's also the small possibility of being trampled during Black Friday, but everyone should be aware of that issue.