A garden tool or some kind of club can quickly dispatch a rabid animal in such situation. Of course, I'm speaking from experience, I had an aunt that was in her garden when attacked by a rabid fox. She killed it with a garden hoe without being harmed.
Is it really going to be any easier to hit a wildly-moving target at zero range? I would think that the amount of uncertainty related to motion of the object between the trigger finger's command to fire and the arrival of the bullet would be relatively independent of range, at least up to 50' or so, and control of the weapon would be much easier if one's target is moving over a smaller angle. Rifles are not meele weapons.
As for the woman's life being at risk, she'll probably want want to get rabies shots whether or not she was infected (the fox by the sound of it most likely was) but I would think that allowing the fox to continue to bite her would elevate the risk of infection. Not that a .22LR bullet wound is going to help, but I wouldn't consider his actions unreasonable.
Now that you mention it whenever we had to kill things around the farm as a kid nine times out of ten it was always the good ole hoe that got the call.