Four people were killed - including a Chicago police officer, ER doctor, pharmacy resident -- Monday afternoon in a shooting at Mercy Hospital on the city's Near South Side. The gunman, identified to the ABC7 I-Team as Juan Lopez, 32, was also killed. The victims were identified as Dr. Tamara O'Neal and Chicago police officer Samuel Jimenez. A pharmaceutical assistant was also shot and killed, Mayor Rahm Emanuel said during a press conference. Gunfire erupted inside and outside the hospital after 3 p.m. at the main hospital, located at South Michigan Avenue and West 25th Street. Chicago Police Superintendent Eddie...