Miri Shtern’s eyes were wide open, staring straight ahead. Her hands firmly gripped the handle of the Smith and Wesson revolver. Her feet spread apart to stabilize her slight frame, she took aim at the target and squeezed the trigger in rapid succession until she’d discharged the six chambers. Spent shell casings pinged as they bounced upon ground around her boots.

 Twenty-five yards away, the bullets pierced the heart of her target, a paper silhouette of a life-size human being. S...