OFAKIM, Israel — Roni Abuharon, a detective in the southern Israeli city of Ofakim, grabbed his pistol and floppy police hat. “Don’t leave me alone,” his wife pleaded as sirens signaled incoming rockets from the Gaza Strip, less than 20 miles away. Down the street, Itamar Alus, his good friend and fellow officer, told his wife to lock the door and take their children to the bomb shelter. The officers rushed outside. Alus glimpsed his friend from afar, running to meet the sudden staccato of gunfi