In brain science and in hand-to-hand combat, the person who has the ability to calm themselves while under the threat of fighting has the upper hand. A person who can calm themselves can use an incidental strategic advantage collected by their slower upper brain as well as their faster reactions of their reptile survival brain.
A friend of mine was once in a bad situation where a group of thugs were threatening to roll him and rob him. He looked around, figured it would be easier to defend himself if he were in a small space where one person at a time was going to come at him. So he backed in between two parked cars against a dead end wall and proceeded to wait. The thugs taunted each other to go in after him; but eventually one of them said, "Look at him - he's too calm. He's got a gun. Let's go."
Defending oneself in real fight is a whole different matter too, but again - calm observation and questioning one's own assumptions can pay off...
At 24 years old, I was once walking uphill on a one-way switchback to the little Mesa to a party in a remote place in Bolinas near the beach at night. As I walked, I began to suspect that someone was behind me, matching my footsteps. Was it in order to sneak up on me for some nefarious purpose? I shuffled my feet. The person behind me matched my footsteps again. The houses I was passing had occupants who were on vacation, or gone to bed and locked their doors... So I decided my advantage was that he did not know that I suspected what might be going on.
At fifteen paces, I turned around, still walking backwards and started blabbing to him in an over-friendly way in the dark silence. "Oh, hi! Were you at the beach like I just was? I didn't notice you there. Did you get that shirt at the freebox? I love the Freebox... I'm going to a party; are you going there too? "
He stopped, somewhat shocked...not answering me. Which indicated to me that he might have the nefarious intentions I imagined. Now I knew how he was dressed. But there we were...walking along, twenty feet apart. So I kept blabbing to him and decided to choose my battle ground to conduct a little test. I wanted to control where I was going to allow him to get closer to me to see what he might do when we came to a steep switchback.
When I reached my chosen spot, at that point I said, "Oh shit! Forgot something at the beach, gotta go back..." Sure enough, he ran the last ten feet uphill across the street towards me and pushed me down. But because I was smart to think ahead, I was on the ground parallel to the outside edge of the road; next to me was a steep drop off. I had a significant advantage of familiarity with the terrain.
While I was on the ground as he was coming close to me, I realized that my legs were a whole lot longer than his arms. I remember thinking, "Some part of me must have been planning this." As he loomed over me, still saying nothing, I crouched in a fetal position, saying, "Oh, you're going to help me up." He still said nothing. As he bent over me, all I had to do was extend my legs and plant them in his crotch to toss him over the steep edge of the road. I got up and ran. When I breathlessly arrived at the party, I explained what had happened. The guys in the part all went out looking for this attacker. But there was enough time to for him to disappear.
Later in the daytime, I went back to the scene of the crime. I saw that what I had done to evade the attack was an even better plan than I imagined. Where he'd landed off the side of the road, there were many poison oak bushes...