You’re a police officer who just pulled over a car. The driver looks as if he’s aiming a shiny object at you. Is it a gun or a cell phone? Do you shoot? Ripon police officers are practicing handling such life-or-death decisions. They are testing firearm simulations systems for the U.S. Department of Justice. Sgt. Timothy Bailey trains Wednesday as Sgt. Steve Merchant works the computer that controls scenarios that can change in real-time based upon the trainees’ reactions.