In an interview with NBC's Today show, Officer Mark Dallas said, "I'm dad to all these kids... these guys, especially the senior class."
"It happened extremely fast. All my thought is - oh my God he's going to get somebody over there. I need to continue, continue. I was not going to let him get away," he said on the show.
Dallas arrested 19-year old Matthew Milby.
The high school senior has pleaded not guilty to felony charges for using a 9mm semi-automatic rifle during the school shooting.
No one was injured.
Even though he was facing gunfire, Officer Dallas said his training automatically kicked in.