I watched the uncut video of the entire Texas church shooting. The thing that struck me was that the gentleman who was killed didn't appear to comprehend what was happening until it was far too late for him to do anything. The killer already had his shotgun up and pointed when the gentleman started to get up off the pew, let alone start to draw. At that point, it wouldn't have mattered if he had his weapon in his hand. The killer had him covered already. It was just far, far too late.
In no way do I pretend to be an expert in armed confrontation. I practice, but not enough. The one time I used a handgun to thwart an assault (no shots fired), I could see the situation developing and was ready. But situational awareness, to me, remains at the top of the priority list when it comes to preparation. As I told my wife: if I see a guy enter a crowded place covered head to toe and acting weird, we're either outta there or I have my hand on my weapon. If SHTF, I HOPE I'm not gonna be sitting with my hand up on the back of the pew or couch or whatever watching in disbelief. In training scenarios. I KNOW I'm prone to tunnel vision; it's gotten me "dead" from only watching the obvious.