Why didn't she simply start unloading her pistol and shotgun into these attackers?
As Kevin Costner said in the "Untouchables": "Shoot a couple and I guarantee you the rest will run away".
Because an officer knows their career, reputation and freedom could well end with that?
Some lives are more precious than others.
I prefer the logic from this scene in the movie Tombstone. https://www.youtube.com/watch?v=co5xVHsMRV0 “Your friends might get me in a rush, but not before I turn your head into a canoe.”