I was one of those.
FoF really drives home the lesson that decision-making is SOO important to such scenarios. Not just gun-handling and marksmanship alone.
Force on force training may be about as close as you can get. But it's still just that, training.
For example, but how do you think you will react to a shooter if your wife takes a gunshot to the face?
Will you move to shield and protect her, stand there in shock because of what just happened and what you see in front of you, or will you be drawing your gun?
Someone asked me that once and I don't really know the answer to that.... I couldn't know, having never been in combat or a gunfight.
These are things we can't practice or know, until we face them.