Learning to use a semi-auto isn't that complicated. It's not like trying to learn to speak Basque.
It's nice that the owner put all those guns there for the employees to use if they needed them. A lot of corporations that run convenience stores forbid the store employees from having guns to protect themselves. Of course, the lamestream media will never criticize those corporations. They'll be too busy whining about Halliburton.
While I doubt she would have any trouble in a heated situation, my wife has a difficult time with the slides of some guns.
In the heat of the moment, one extra step might be enough to change the situation from a pleasant one to a not so pleasant one.