Cite your source stating that good guys with guns can prevent all mass shootings. Let me help you, it doesn’t exist.
What we know for a fact though is that the quicker these shooters can be engaged with gunfire the less the likelihood the death toll will rise above three and that the incidents will typically end in less than 1/4 of the time as compared to when they are given a free opportunity to shoot to their heart’s content.
In this case the shooter had an elevated and fortified position, long guns, and still was only able to kill one person. That’s a win every time.
