From a Fox News report of Arapahoe County Sheriff Grayson Robinson’s press conference: When an armed school resource officer entered the room, Pierson believed he was cornered and turned his gun on himself, Robinson said. The entire attack lasted approximately 80 seconds and was captured by security cameras. Sounds like that SRO stopped what could have possibly been a much bigger tragedy. It’s a result that we expected, based on our own independent testing of school shooting scenarios. If that armed resource officer hadn’t been present, it would have taken even more time for the police to arrive and stop him — time the shooter could have used to killing more people. Instead, in the oft-ridiculed words of Wayne LaPierre, a good guy with a gun stopped the bad guy with a gun.