In the case of a school shooting, everyone involved with the school is affected.  Students, teachers, and parents are all affected in their own way.

Being affected during and after a school shooting can cause damage such as having the memory of the event replay over and over in your mind. If you were really affected during a school shooting, the damage is way more severe, because besides from being shot you will have witnessed others getting hurt, or even dying, not to mention having that livid memory in your mind for the rest of you life.  The shooters themselves have to take the consequences of their actions.