I have in fact been shot by a .22 Tenex round (by an idiot in the next rifle station at summer camp) and it barely penetrated the skin under my T-shirt. (I was sure for about 15 seconds that I had been killed, but that's another story.)
I don't think anybody here disagrees that a .22 in your pocket is better than a .44 Mag you left at home, but all other things being equal, Mr. Rutherford needs to up his caliber as far as he comfortably can. Next time he might not be so lucky.
But most criminals (other than the psychos and the crackheads) are essentially cowards, and the mere fact of fighting back will cause most of them to run. (It's the other ones you need to worry about.)