You want personal experiences? I am a US Army reserve military police officer (CPT) have been for 10 years. I also have a concealed carry permit.
Several years ago I came home to a burglar in my home. The guy had used a crowbar to force the back door. Had I been unarmed, he would have either a.) gotten away or b.) beaten me to death.
As it was, I was able to hold him at gunpoint for the 20 minutes it took for the sheriff's dept to arrive after I called 911.
While deployed to Ft Benning, I responded to a domestic call. Even though it took me less than 3 minutes to arrive on scene, the husband had stabbed the wife in the chest with a butcher knife and slit his throat. She was dead at the scene and he bled out while waiting for the paramedics to arrive.
Point is, you cannot rely on the police being there in time to save your life in a crisis. We/they do the best we can but you cannot change the laws of physics.