We have to establish initial control to the extent possible until the police department arrives and take control of the situation.  The first officer to arrive becomes the on-scene commander.  Until that happens WE must know where the shooter was last, whether we have injured or dead, and prevent to the extent possible any further deaths or injury by not making ourselves available.

If you can imagine the mindset of someone who has committed this type of crime, they will probably have a sense of not having much to lose and will keep killing and in most cases kill themselves.

Shooting events in the workplace can be triggered by a number of events:

Domestic situations that come to the workplace
Disgruntled employees
Fired employees
Students angry with the school or instructor
Students with gang affiliations bring the fight on campus
Drug transactions that go bad.  Do we or have we had drug issues, YES.

Our best defense is to know our procedures, be observant and report anything you suspect is out of the ordinary.  I would rather be wrong than make an assumption and we lose people because we have failed to act.