Austin 1966 (or 65) had one of the first mass shootings from the UT Tower.
Right. Back then, the imprompto citizen militia (many of them Korean and WW II vets) took their long rifles from their pickup trucks and engaged the shooter, keeping him pinned down until two brave Austin cops, accompanied by an armed civillian veteran, got to the top of the tower and killed Whitman.
Look at a documentary and observe the number of builllets impacting the tower that were largely fired by the civillians. Whitman did most of his killing before being engaged and supressed by civillian shooters.
SWAT was not a meaningful concept back then.