An elderly man lost his balance on an escalator and fell back on his wife when they were exiting a subway station in Shanghai on Tuesday. In scenes captured by a surveillance camera, an astute passenger pressed the emergency stop button at the bottom of the escalator. His quick reaction saved the old couple from serious injury. At the end of 2015, China's Administration of Quality Supervision, Inspection and Quarantine did a massive safety inspection of escalators following a spate of accidents. It found that more than 110,000 had potential safety issues.