Let's say you’re being held hostage by a dangerous armed criminal who has already harmed others and is threatening to kill you. The police arrive, and the criminal demands to know if there are snipers positioned outside. If the cop truthfully says “Yes,” the criminal might panic and shoot you immediately. Instead, the cop lies and says, “No, it’s just us talking, let’s work this out,” buying time for a sniper to take the criminal down and save your life.