In a quandary
I (with my brothers) started jujitsu when I was in highschool about 30 years ago for practical self-defense purposes (my father forced us into it).
My sensei (whom he said trained in Kodokan) was also a petrol station owner and has had his share of fights with robbers, muggers and drug addicts. We lived in a not so ideal neighborhood back then. He would tell us stories of his encounters and would show us his stab wounds and the numerous bones that he's broken in his jujitsu career. He even showed us a newspaper clipping how he'd beaten robbers to a pulp when they tried to rob his store and tried to stab him. You can tell that he's a no-nonsense guy.
For the years that we've been training with him, he only taught us mainly knife defenses namely shoulder udekimenage, hijigime, arrest techniques like standing nikyo pin as well kicking the bag/boxing. He didn't even teach us jujitsu basics when I think about it. He must have this street-experience he thought of what minimum techniques he'd teach us would be most effective out in the street. Mind you, the shoulder udekimenage is a bone breaker similar to the nikyo pin, not just submission or throws.
Fast forward several decades, life happened. I have come to love the aikido lifestyle (being non-violent) but have now forgotten how to treat someone that would try to harm me "properly". My old teacher would say that when you encounter a drug-crazed person who's running amok, they wouldn't feel pain even if you break their bones and would continue with their aggression unless you make them really submit which is hard to do given that they'll feel no pain. Or if you encounter a mob, they would continue damaging you unless you do semi-permanent damage on them. He said to get away as fast as you can but deal with a person no more than 2-3 seconds if it comes to that.
Hopefully I would not encounter such things but I feel that I have lost touch with reality given that our art is a "non-aggressive" one.