The conventional wisdom is that, when meeting with a person who may become violent, you should sit near the exit, so you can escape if something goes wrong. Unfortunately, this can leave you in a position where the assailant will pass near you on the way into or out of the room. So, which is better -- to stay as far from the person as you can, and keep him or her in sight, or to stay close to the exit, and be on guard as he or she comes and goes?
Ideally, you should do both. If you can choose a meeting location with multiple exits, that is best. You can keep yourself near one exit, and have the other person use another exit. If not, then try to arrange for the other person enter first and sit farther from the exit, so you can be close to it. If this is not feasible, then pick a spot that is closer to the exit, and be more ready for an attack when the other person enters and exits.