Not quite. The murderer attacked victims in four seperate classrooms in Norris Hall; an effective defender would have had to have been in the first room attacked to have *greatly* reduced the toll, and that's where the killer had the greatest element of surprise on his side. More likely: a single armed person in one of the four classrooms would have had a good chance of cutting the toll in half, as the odds would be one in four that he would have been in the first room and thereby would have had a better chance of being warned by the first shots elsewhere or by a witness. But even cutting the toll of dead and wounded by one-fourth would have been an improvement.
Better: had there been an armed student or university staffer in each of the four rooms, it's almost a certainty that Cho would have been less successful by half or three-fourths. Once warned by the first shots, those in other rooms could have taken cover as available and been waiting and ready, instead of trying to hide in adjoining closets or jump out of upper-story windows.
But if every person in that building had been effectively equipped and at least minimally trained, it's most likely Cho would have not completed his atrocity in the first room he attacked. There might be three, even five dead, plus the death of the perpetrator. But it would have ended there.
I wish that old Romanian Jew who had survived the Nazi Transnistria labor camp and had an instructor's grasp of technical and scientific skill had stood in that doorway with whatever effective tool he thought most suitable for his circumstances. Had that been the case, he could have protected his students by doing something more effective than using his body as a sandbag.
You overlooked (unintentionally I’m sure) my other comment.
The one about if CCW was in play on the campus, Cho wouldn’t have known who was armed in ANY classroom, and therefore wouldn’t have choosen as he did.
I think that part of my view counters your well thought out post to me.
What do you think?