I have awoken with my hand curled in some Seagal-like geometry angles, been completely numb before and I have thought the same thing, "what if?".
I'd like to agree with Dog that adrenalin would take over and it would be a non-issue but if it doesn't.
I didn't always train to shoot off handed, because I shoot with my non dominant hand, keeping my dominant hand able for force manipulation, but now I active train to shoot with my "off hand" just in case.
Thankfully I have a couple of very loyal German Shepherds that would probably tear a bad guy to shreds by the time I got to him.
I do love my four legged protectors, they are the best.