"What happened next? Did the guy go down? KO? ...none of the above, he merely blinked once and carried on fighting - it later took a headlock to restrain him!"
Yes. Thank you. Alcohol/drugs and adrenaline have an effect on how someone reacts, not just ki. How do you disrupt someones "PCP"? That's why submission is so important. If your up against two people on PCP? Run!
As far as pressure points, it's helped me escape having to tap-out during BJJ practice. A nice stiff finger in the ribs will work, but I'm not so sure about in a real life situation w/adrenaline.
And, I think it would take just as long to learn effective pressure point use as it would to learn effective technique. People often think that there's some magical point on the human body, and if I only knew where it was... It's not that easy.