“This is an elephant,” the trainer declared. “And we’re eating it one bite at a time.” No, the trainer wasn’t at a restaurant getting ready for a competitive-eating contest. Rather, Joe Sandoval, of Mindset Tactical Solutions LLC, was talking police tactics – specifically, how to properly clear rooms during an active shooter response. His point to the four-person team of Tustin PD officers who were making their way through an abandoned building on the old Tustin Marine Corps Base was to stress the importance of quickly and methodically declaring rooms clear of danger, and not going rogue to try and…