Incredible. If you hit the link the story includes a video interview with Kaylub.

Passing by the school that day, Giamanco spotted someone carrying a gun, followed him into the school, and then shot and killed the teen who fired shotgun rounds into a special education classroom. The shooter killed three children, ages 5, 8 and 11, and a 25-year-old teacher. Two other people were seriously injured. Police credit Giamanco with saving many lives at the school of more than 400 children.
But before all that, there were years helping a single mother as the oldest of seven children, there was the motorbike accident when he saved his brother’s life with a makeshift tourniquet, and the informal military training he’d gotten from Iraq War veterans. A lifetime that shaped Giamanco, he believes, and prepared him for what he would do next.