Idle and sad speculation on your part. Inaction was the death warrant of many that morning -- that we know.
We have the stories of the living. None of them threw books. Some played dead, or just hid under desks. attacking the shooter could not have had a better outcome than that for those who survived.
That we know.
We don’t know exactly what every one of the dead people did. One of them held a door shut, one of them confronted the shooter instead of staying safe on the 3rd floor.
That we know.
None of them had a gun, because people who never have to worry about being in a situation where they need a gun decided everybody would be safer if nobody was allowed to have a gun.
That we know.
And we know that, for those who had enough time to think, many of them reacted admirably and saved themselves and others, by barring the doors.
That we know.
Everything about throwing books, using non-existant fire exinguishers, rushing a guy with two semi-automatic weapons — that’s the speculation.