Complex sentence: Chris Mintz, a U.S. Army veteran, ran into the building where the shooting was taking place and attempted to block Harper-Mercer from moving into of a room, and was shot three times while standing, and another four times while injured, but survived.
Split into simpler sentences: Chris Mintz, a U.S. Army veteran, ran into the building where the shooting was taking place and attempted to block Harper-Mercer from moving into of a room. He was shot three times while standing, and another four times while injured, but survived.