TOKYO (AP) — A fatal fire on Japan's bullet train, started by a man who self-immolated this week, has revealed blind spots in a system renowned for its speed, punctuality and safety record. Experts say it was a wake-up call to something more disastrous, potentially a terrorist attack, and it's time to step up risk management ahead of the G-7 summit in Japan next year and the 2020 Tokyo Olympics. [...] authorities haven't found any mishandling by the train operator, but the initial investigation and witness accounts have raised questions, including how quickly crew members grasped the situation and whether there should be a better way to clear smoke from the hermetically sealed cars. In a standard emergency procedure, the overhead electric power was cut off for a 20-kilometer (12-mile) stretch to keep the tracks clear for police and rescue workers, also shutting off the train's ventilation system. A 1964 law on violations related to bullet train safety doesn't mention arson, and even today, inflammable ceilings and fire-retardant seats on the train are mainly intended to prevent fire caused by glitches, experts say.