Hmmm........not sure why you wouldn't simply finish the choke if you have it locked in - surely it's less damaging and painful than breaking the opponent's jaw? Proper RNC will have the opponent out in <10 seconds.

BTW, It is possible to break someone's jaw from choke positions . I almost found out the hard way, although not from the RNC -
"In case you ever wondered what it's like to be knocked out, it's like waking up from a nightmare only to discover it wasn't a dream." -Forrest Griffin