My context is effective personal protection/learning how to fight with a gun and that is what the woman in the OP was wanting, but what she received was a shooting/shooting sports perspective as these statements from it illustrate...

"Taught proper grip, stance, sight picture, and trigger control. Absolutely accurate on steel targets at 15 yards. 10 for ten after the second mag for 7 mags worth. She had a smile on her face."

"I have seen so many who were not gun people get pushed into bigger guns they could not shoot accurately, properly manipulate, or felt uncomfortable with and ended up either abandoning the sport or just throwing it in a drawer never to use again or rarely using it."

Civilian self-defense encounters are almost always quick, dirty and occur at contact or point blank ranges. How to get the weapon into the fight is obviously vital and often extremely difficult, but seldom trained by "shooters". The same applies to weapon retention. Firing from stable stances, with a secure two handed grip using a traditional sight picture is not something that is likely to occur in an actual civilian scenario. Since there was mention of a "client" being a possible threat in the OP, that tells me she is working in close proximity to the individual(s) she is concerned with, so a contact scenario even the more likely. Despite what some instructors may say, it's difficult to keep a semi-auto running in an ECQ situation no matter the training of the individual.

Semi-autos need a certain amount of stability to cycle reliably, but will she be able to keep that .22 auto running while moving, with a ****** one handed grip, while possibly being in physical contact with her assailant? Maybe, but I wouldn't bet on it. Plus figure in the finicky nature of .22 autoloaders and of rimfire cartridges themselves. Consider the low stopping power potential of the .22 combined with an untrained woman, who may possibly be older, so situational awareness, reflex and quickness of action and thought aren't going to be on the high end of the spectrum, meaning it going to contact highly probable. If if she has distance, she would likely run out of time.

I've come to notice gun guys seem to have a certain disdain or dismissal for physical fighting and like to take the perspective that they will always have a certain amount of time and distance on their side to effectively "smite their foe" from a safe distance and that that they will be capable of doing so despite no training beyond static range work, but that unfortunately isn't reality. And while I would absolutely agree that the vast majority of civilian armed defense situations are resolved by simply producing a weapon or as soon as shots are fired, that cannot and should not be counted on. She may not be able to break contact or convince the assailant(s) they have somewhere else to be and should move on to another easier victim. She may have to physically stop them and I just don't think a .22 is acceptable in that context, because even if there is adequate separation to get off multiple shots, she would have to make fairly precise hits, while in a panic, against a moving target, while she is likely in motion herself, which she will likely never practice and even if she did, that would be an ideal scenario not what is likely.

I think she would be much better armed with an enclosed hammer snub in .38 special. Standard pressure ammunition is extremely mild and neither my wife, mother or even grandmother(in her 90's) have any significant problems with it. If she absolutely insists on a .22, there are choices available in revolvers.

From Massad Ayoob...

The Real Ladies Gun -- Handguns