Bean Station is not far from me, I heard about this earlier. What a horrifying situation.
I don't know what the policies are regarding carrying in a pharmacy, but most businesses don't allow employees to carry during work hours. I know ours doesn't, except for office personnel.
The perp being an ex-LEO makes it all that much worse, especially killing them after they complied with his demands. Not too long ago, about 6 weeks ago?, one of our stores was robbed at gun point, the Manager complied and the thief had her laying on the floor face down. She said all she could do was pray that he didn't shoot her anyway. He didn't fortunately. (he was caught later after robbing another store of the same type)