An employee was cutting wood and installing wood backing in an elevator shaft. He retrieved a rolling baker scaffold from the drywall crew and positioned it near the work area. He placed the wood on the scaffold and climbed up. While nailing a piece into place, he lost his balance and slipped. To steady himself, he grabbed the newly installed wood, but the wood detached and he fell into the elevator shaft. He sustained fractures to his ribs and pelvis and a laceration to the head.