Sometimes you just get lucky.
I went to the city yesterday. A family member had a doctor appointment. Before heading back home, we stopped to pick up a few things at Walmart. Moments after we left, probably before we even were out of the parking lot, someone was shot and killed inside the store. https://www.lubbockonline.com/story/news/crime/2020/12/04/police-investigating-deadly-shooting-north-lubbock-walmart/3832945001/
Part of me is glad I would have been prepared to deal with a bad guy-- as long as my situational awareness was what it should have been-- but mostly I'm glad I was lucky enough to have forgotten about the 4th item I intended to get. Any delay would have put us in the store when the shooting happened. Any delay at all.
I doubt there was much danger to anyone but the victim. It sounds like a targeted attack. Probably not even worth the risk (physical and legal) of drawing on the shooter. But it's still better to be armed than not.
No matter how prepared you are, luck is going to play a part. You may be able to stack luck in your favor by being prepared, but you can't plan for everything. This is why situational awareness is so critically important. Always. "It can't happen here" is guaranteed to be wrong.