it would have been so hard to lock down everything with all the students go to and from class, lets focus on giving our respects to those who died than making assumptions, we will never know if they could have saved more lifes by shutting the campus down, at the end of the day this person wanted to die and take out as many people as he could with him. There is no procedure for dealing with this, a shooter has never come back to a different area like this situation, its just to hard to predict so stop blaming the school and the police cause they did there job as best as they could