never done an active shooter or lockdown drill. and the schools don't have guidelines to use in training. >> reporter: the goal of any drill is to make sure the reaction to the emergency becomes second nature. this is a lockdown in lakewood. the students know exactly what to do and where to go. the principal helped set up a camera inside the classroom. district does two of these in every school every year. >> we're at 2.1 years since the arapahoe tragedy. in my world, time is running out for the next one. >> reporter: an investigation found lockdowns or active shooter drills look different from district to district, if they are done at all. the drills aren't mandated.