TSA agents do not get paid very well. Main requirement for the job is a background check. I think there should be "trained" armed, TSA agents at every security check point. If not them, then police officers or military.
One thing I've been thinking about is that us being deaf, we would not hear gun shots. We definitely would see the people running but would have no clue why.
Also...in watching this all go down on the news, does anyone think that the emergency response was too much? There were over 100 emergency vehicles. Seems like that in itself makes the scene that much worse.