An electric gate at a third party facility would not operate. The pin pad had been disabled and the chain had been unhooked from the operator for the gate. An employee was manually opening the gate (pushing it open) when the chain got caught on a bolt or other object. While the employee was trying to release the chain, the gate moved, causing the employee's hand to go through a roller. He sustained contusions and lacerations to four fingers and a partial amputation of his left middle fingertip.