My defensive mindset is pretty simple. I do what I have to.
The other night, my friend was attacked by a drunk at a bar who thought he had stolen his beer. The beer in question had been in my friend's hand for 15 minutes. It was nearly empty.
The guy had the drop on my friend and was choking him senseless. I cut in and pushed the guy off and yelled "STOP". That didn't work. He closed in on me, proving that he was either crazy or extremely drunk because I'm an avid weightlifter and outweighed him by at least 100 pounds. He reached for my throat as he did my friend, and I caught his hand, twisted his wrist sharply to the outside, and put my knee into his crotch. He crumpled up on the ground holding his broken wrist. The friends of the deranged individual came after me next, and I again shouted "STOP", but that did not work. Security was just now realizing the situation and was making their way toward us, but I had nowhere to run to and two guys similar in stature to the first attacker tried to get revenge. I threw one punch and that pretty well ended one man's will to fight, and security grabbed the other guy before he could do anything.
Security gruffly threw the three guys outside, and asked if they could speak with me outside. I agreed. They asked why I was fighting in their establishment, and I told them what had happened. A witness who was leaving the bar at the time confirmed my story, and the three guys were told to leave immediately or the police would be called.
I told them that I had to do what I had to do. I've never been in a serious fight in my entire life, and have never gone looking for the experience. I can't see why anyone would. This happened a little more than a week ago and my hand just today stopped aching. I was lucky that was all I went away with.
When people with bad intentions come your way, you should get out of there if at all possible. If it's too late for that then you have no choice. You will be killed or seriously injured if you don't have the will to act when necessary. You can train and learn new skills as much as you like, but if you don't have the courage to resort to it when you need to, it was a waste.
Stay aware and stay safe.