I have been reading "Security for Court Interpreters," published in 2006, and I would recommend it as a good foundation for learning about safety in courtrooms and other typical legal settings. It is a bit long (310 pages -- though many are blank or contain little information), but reads quickly. Though it is directed towards court interpreters, the advice it contains is applicable to anyone who works in a legal setting.
All of the items in a courtroom, conference room, waiting area, office, or any other location can generally be divided into two groups -- obstacles and weapons. The dividing line is basically whether or not the item can be readily lifted.
Desks, heavy chairs, railings, the judge's bench, and such are obstacles. You will have to move around them if action is necessary, and they can be useful in impeding the movement of an assailant, providing hard and sharp surfaces to throw an assailant against, or possibly even as cover or concealment.
Pens, clipboards, briefcases, light chairs, and such are weapons. You can move these items to suit your purposes. These items can be used to attack an assailant, to block an assailant's attack, to trip an assailant, or to cause distraction. Unfortunately, all of these uses are available to an assailant as well as to you, so be careful around moveable objects, and consider all the different ways they can be used.
The next time you are in court, a conference room, someone's office, or whatever arena you visit in your practice, look around at the items in your environment and consider these uses.
For those of us who regularly attend court, we usually think that the courthouse is a gun-free zone. Maybe not. A recent incident shows that even with security personnel and full-body metal detectors, it can be relatively easy to get a gun into a courthouse. Because security staff may be lax at times, it is important to keep aware of potential threats. Read the article here.