In the same vein as my earlier suggestion to buy armor for any screener who wants it, TSA could put snare nets on the ceiling over every checkpoint. Anything bad goes down, instead of calling a Code Bravo, they just push a button and everybody in the area gets snared. Keeps the bad guy corraled while LEOs show up. Keeps the passengers in other areas of the terminal safe.

Might have a bad outcome for the innocents trapped along with the bad guy, but it's like being on the undesirable side of a waterproof hatch as the ship goes down. Sometimes you lose the draw.

The greatest good for the greatest number, and all that.