I recently had an experience in my office with 2 large, young guys were acting very strange. One of them got aggressive with me. I only have one door in my office.
I stood up and walked past them and said, "follow me" and they did and then I said, "come on over here". They followed me over to the gate.
I pointed and said, "stand over there" and they did. I went through the gate, slammed it shut and got in my car and drove off.
I was very centered and still and knew exactly what to do. The guy that was aggressive has not been back in the office since and he calls to pay on time with his credit card.