EE STATES THAT AT THE END OF HIS SHIFT, HE LEFT THE CENTRAL OPERATOR'S ROOM AND WENT TO THE ELEVATOR, RODE THE ELEVATOR TO THE FIRST FLOOR AND WAS EXITING THE OUTSIDE DOOR WHEN HE STEPPED ON A SMALL PIECE OF METAL LYING ON THE ASPHALTED AREA. WHEN HIS FOOT CONTACTED THE PIECE OF METAL, IT CAUSED HIM TO TWIST HIS LEFT KNEE AND ANKLE. INDIVIDUAL HAD ARTHROSOPIC SURGERY ON THE SAME KN