Being in an up-in-your-face shouting match with someone can be very uncomfortable, but it is not necessarily life-threatening.  Because such a situation may escalate to physical violence, you should avoid it and walk away if possible.  If this is not possible, then stay calm and observant, and try to defuse the situation.

First, assume a non-threatening but still defensive posture.  Take a small step back with your dominant foot (it's the same side as your dominant hand) and hold your hands open in front of you, with the palms facing your antagonist, at about chest height.  Speak calmly with the person, and do not shout back (though you may have to raise the volume of your voice to be heard).  This will allow you to be on guard without being provocative, and give you a bit more distance.

Keep your eyes open for signs of an imminent attack.  These may include the person's face going from red and flushed to pale white or a sudden dilation of the pupils (signs that the sympathetic nervous system has engaged), clenching the fists or turning to the side (both signs of an intent to strike), suddenly looking around (for witnesses), or suddenly becoming quiet.  If any of these things happen, or any other abrupt change in behavior occurs, be ready to fight.

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.

Yesterday I was searching for a passage from the Tao Te Ching that I think is helpful (it's chapter 15), and I came across a martial arts blog that lamented the culture of non-violence in America. Sure, you shouldn't be violent, it said, but we've gone too far -- now you can't even stand up for yourself and get into a shouting match with someone without being accused of "making terroristic threats."

Such an attitude is more likely to cause problems than to solve them. As people become more prone to expressing their animosity with gunfire (such as in the Mark Hummels tragedy), having a "you gotta stick up for yourself" mentality can lead to violence, rather than avoid it. I prosecuted a disorderly conduct/threats case once in which the defendant claimed that, as a trained martial artist, he felt justified in telling a store loss-prevention officer, "if you don't get away from me, I'm going to f**king kill you." This, he claimed, was a response to concern about the person following him in a crowded store.

If you are concerned for your safety, do not seek a confrontation with the person(s). Seek safety and assistance. Engaging an unknown assailant -- even verbally -- should be a last resort, because you do not know how that person is armed, trained, or influenced by drugs or alcohol. Sure, it may sting your pride to "back down," but that sting hurts less than a bullet.