Something big going on at King Soopers on Table Mesa in Boulder

[.455_Hunter]

I read SOTI (somewhere on the internet) that most "mass shooting" events last less than 5 minutes before either LE responds or the shooter takes himself out. I think the VA Tech shooting was the rare exception where it lasted something like a half hour or an hour at multiple locations but that's uncommon.

My point being that unless you are physically there, by the time you "hear about" a mass shooting, the shooting is likely over.

IIRC the main "lesson" of Columbine, where the responding officers (following policies that were in effect at that time) waited for backup before going in, was to change that policy and now the policy is that the first officer on the scene goes in, regardless of whether he has backup, because every second that the shooter goes unchallenged is an opportunity for him to shoot more people.

Agree 100%. The key recent times that has not happened have been in Florida- The Pulse nightclub and Stoneman Douglass HS come to mind, with active killing occuring inside while armed response was staying outside.