I don't believe getting knocked out is about force or hard chin, Cormier just has good awareness of himself and his environment, he's a realist and doesn't panic.
Little personal story, i had my jaw broken in four parts once when i fell off my bike at high speed, i fell head first on asphalt and i knew i was about to fall a second before it happened, i was just too fast and couldn't stop, but i saw the mistake i made, i wasn't out or dazed for one second, i even had to rescue myself, seconds after the impact, because it was dark and i fell on railroad and the tram just had arrived and was about to run over me and my trashed bike.
To me it felt like i was even more awake then normal, because i was in complete survival mode. My arm was broken as well, four weeks in hospital, a complete desaster.
How is it possible i wasn't out after this kind of impact if getting knocked out is about force or hard chin?