Yes, the 22 is lethal and with any caliber, just like business placement, the key is location location location. Well, except for that pesky little thing called "the pucker factor".
I don't care what caliber you use or how many times you pull the trigger when your azzhole puckers to the back of your throat you'll be lucky to hit what you're shooting at.
Typical hit ratio for most LEO at combat ranges, within about 15ft is lower than one might think.
Here's one of the first studies on the subject.
http://www.pointshooting.com/1asop9.htm
Granted the study is not current but Bruce K. Siddle (Detonics) has been studying and teaching about combat for years and these statistics haven't improved that much. This is a good read.
http://www.amazon.com/Sharpening-War.../dp/0964920506
Training helps obviously but that pesky ole pucker factor keeps messing with our ability to hit what we're aiming at under stressful situations.
I know I hit just about all the animals I ever shot at in my life except for those that were shooting at me. I have no idea how many of them I actually hit.