There is just no such thing as perfect adherence to procedure. People are people, not robots, and they will inevitably get careless from time to time. Practice and procedure are there to make sure that the right thing happens as often as possible and minimizes the opportunities for someone to take advantage. Most of the time, it works right. If that wasn't the case, then what happened today wouldn't be so newsworthy.
It is newsworthy because it very rarely happens.
Furthermore, if there was any lapse today it was in not double-teaming the perp. The gender of the deputy isn't nearly the issue. One-on-one is really bad odds nomatter who the deputy is. This perp is apparently even an ex cop. He's smart, and he knows the drills, and it makes him a very effective predator.
Where did you hear he was an X-cop?
That would explaine how he knew the "secret" of getting the gun out of the holster, that the talking head wouldn't show on FOX news.