https://www.ready.gov/active-shooterTalking about this can feel a little weird, but it should. Many of us tend to forget about ourselves and help others, and having to tell you not to think that way feels a bit cold hearted and insensitive, but there is no way you can help even one other person if you are not taking care of yourself first.
If you see someone you think may have a gun on them, say something. It is posted in several places in the building that we don't allow firearms.
If you see someone acting suspicious, say something. Even if you think you may be reading too much into it, being wrong is better than being right and not telling anyone.
Look around, do your windows open? What does the path to the front door look like from your office? How difficult is it for you to get out of your office, or hide in your office? These are things you want to think about. The less your brain has to work on figuring those things out, the more time you can focus on getting to safety, or even helping others if you are already safe.