Complex sentence: Reaching the medical building, Lopez injured a soldier walking outside before entering and fatally shot a soldier at the main entrance desk, Staff Sgt. Carlos Lazaney-Rodriguez; he also wounded another soldier inside.
Split into simpler sentences: Reaching the medical building, Lopez injured a soldier walking outside. He then entered the building and fatally shot a soldier at the main entrance desk, Staff Sgt. Carlos Lazaney-Rodriguez; he also wounded another soldier inside.