Since you can't recognize the entire threat, it then falls into whether you should even address it.
LEO/MIL are dedicated to that job. You hire them to do it - they run to the sound of gunfire. It does NOT mean that any CCW in the area of gunshots should.
If alone, you still have the responsibility to protect yourself in the least lethal manner possible. We often discuss that we need to present and fire in the face of a lethal threat (and in LV it remains to be fully revealed what went on.) What should be the OBVIOUS corollary is that if no threat is immediately present - don't go looking for it.
In typical male society, running from the fight is considered cowardice, when the reality is that elevating the threat and becoming a dead victim won't help at all. Brave dead heroes get a lot of nice press, but their family would just as soon have them around. And counselors get to hear that over and over and over.
Sure, you should have situational awareness, the responsibility is to get out alive first and foremost. Until you are presented with lethal force - you have no obligation to respond to it.
Case in point, an employee confronted by armed assailants exits the building, retrieves his handgun from his car, reenters, and shoots one. Pretty much absolutely required of a cop on duty to perform in that manner, but no obligation exists for someone who has left the scene.
The problem is that we keep looking up to LEO/MIL as a standard of ethics in our tactical performance - but the average CCW isn't LEO/MIL. They are a citizen - responsible to perform in what a reasonable person would do when viewed by a judge and jury.
A reasonable person - in this day and age, like it or not - does not seek out confrontation. Especially with little training or skills to address it. Having a CCW license does not qualify the carrier to engage in sophisticated armed exchanges, any more than having a Driver's license gets you into the grid at Darlington. If anything, you'll get shunted to the wall so the big boys can get on with the race.
It's beginning to appear more and more that may be exactly what happened in the LV Walmart, and the antigunners are now using that as an example of why there shouldn't be any CCW at all.
So, while we do need to bone up on being situationally aware, you can only see what you can see - which isn't an omniscient view overhead. It's limited to your line of sight AND understanding, which will never be complete.
If no gun is pointed at you - you are under no obligation to even reveal you have one. And you get to go home to your family. The cops will thank you, the medics will thank you, and the coroner will thank you because you didn't add to the burden of their workload.
Harsh reality, lets not approach carrying concealed with the same perspective of open carry zealots toting AK's in Home Depot.