A NON EMPLOYEE TRUCK DRIVER WAS ATTEMPTING TO HELP THE TOWMOTOR OPERATOR WHO WAS STUCK ON THE ICE ON THE LOADING DOCK. HE WAS PUSHING ON THE LOAD CAGE AS THE TOWMOTOR DRIVER ROCKED THE TOWMOTO R BACK AND FORTH. AS THE TOWMOTOR ROCKED FORWARD HIS RIGHT ARM BECAME PINCHED BETWEEN THE CAGE AND THE LAST PALLET OF BAGGED SAND, BREAKING HIS RIGHT WRIST.