One of the things I learned a pretty good amount of as a non-neurotypical with really bad emulation in a public school back in the 80s was the way the untrained and poorly trained initiate and conduct violence.
In essence, they pretty much always had a script they'd follow. And they'd follow it extremely predictably, almost religiously. There was nearly always a ritual of pushing, insults, and attempted intimidation that preceded any actual blows. Everything was to be precisely according to the script that they'd constructed in their mind. Did they get this script from watching others, or perhaps from TV? Did it really matter?
One of the things that I learned was that deviating strongly from the script, or preempting them by 'skipping forward a few scenes', would generally give you a significant advantage. They would generally hesitate at least a few seconds, and THEN they'd do the equivalent of 'checking morale'.
The dirty little secret is that schoolyard and bus stop conflicts have a lot in common with ancient warfare---they're more about morale than almost anything else. If you get in the first attack, and press your advantage relentlessly, you will nearly always win, especially if your first strike comes before the actual aggressor had planned to take it. You're also way less likely to be punished by the official authorities if you don't allow the circle of onlookers to form but instead execute a competent preemptive strike once its clear that pugilism is going down today.
It is pretty likely that what the CCW holder did in the Portland mall was break the script of the attacker. By drawing his weapon after taking cover, the assailant realized that the game was up and had to check morale. In this case, as in so many others, his morale failed and he offed himself without the need of any shots fired by the CCW holder. This is likely the main reason why the body count was so low in comparison to so many other such cases. Interestingly, there WAS a no-gun policy at this mall, but fortunately the CCW holder aimed to misbehave. Fortunately also, the lack of a clear shot also prevented him from having to have an up close and personal trip to 'see the elephant'. There is a lot of trauma associated with such trips that I don't wish on anyone.