Some parents are conducting drills at home to teach their children what to do during a mass shooting

McLeod is issuing rapid instructions to her 7-year-old daughter Ella, who is sprawled on her back on a bedroom floor. “Stop breathing so heavy. Don’t move … little breaths, less, less,” she tells the girl. “Relax your face … no smiles, no nothing. Relax every muscle in your body.” The dramatic sce...