CHICAGO — A gunman repeatedly shot an emergency room doctor outside a Chicago hospital, including after she fell to the ground, before he ran into the building and fatally shot a responding police officer and a pharmacy worker as she walked out of an elevator, according to witnesses and investigators. The attacker, Juan Lopez, also died during the shooting Monday at Mercy Hospital on the city’s South Side, but it was unclear if he took his own life or was killed by police, Chicago Police Superintendent Eddie Johnson said late Monday outside another hospital, just minutes after leaving the slain officer’s family. “This officer, all of those officers are heroes, they saved a lot of lives because we just don’t know how much damage he was prepared to do,” Johnson said. Mayor Rahm Emanuel, fighting back tears, said the victims were “all going about their day, all doing what they loved.” He added: “This just tears at the soul of our city.