Nothing even remotely similar to this happened when I was in school. But the following did happen and I don't think is scarred me for life. 1) In school we would practice air raid drills where we would crouch beneath our desks to "protect" ourselves from a nuclear weapon explosion. 2. I lived about 10 miles or so south of an Air Force Base where there were B-52's armed and fueled waiting the the "Ready" area. "Ready" meaning ready to take off in the event of nuclear war. 3. On more than a few occasions, B-52's from another base would stage a "surprise" attack on the local B-52 base at about 5 AM. A "surprise," i.e. below radar, attack by a B-52 at 10 miles out felt like the plane could have knocked bricks off our chimney if its landing gear had been down.
I really don't think these events from my childhood adversely impacted my development. And I pray the school shooting don't significantly impact today's children.