jumped out of the ring and ran away from his opponent because it was to tough after getting pounded a few times?
Charlie Zelenoff did. Twice. But I don't recall any to be honest. Fighters would usually rather get KO'd than running away jumping out of the ring.
there was a story of tommy farr leaving the ring after visiting london because he was terrified of the crowds
That's the first one I thought of too. And Smith was a ****ing badass, kind of puts Moore as a terror in firm perspective. Also, it's funnier than actually running away, he just sort of waved it off and climbed out I think, he was just kind of like "this is ridiculous" more that kind of attitude I reckon which is hysterical.