Thanks you for sharing that moment with us. As a teacher I have had parental situations where we were aware of the what if but it never happened. Just the other day we did a practice lock down at our school. I never thought about it until reading your post but I now realize that I always position myself between where the students are crouched down hiding and the door. I always door a quick hall check before locking the door and as if to keep them better hidden I stand in front of them.
Teaching in Canada I have not had to live with the fear of gun violence on the same scale. There certainly have been incidents, just not on as big a scale. It is terrifying to think that that is becoming a hazard of the job.
Great story!