General Zod
TGT Addict
I kinda got the sense the perp thought the nail gun might break through the bullet resistant glass partition better than his AR. If so, not the sharpest knife in the drawer.
Well, considering he was probably manipulated into the whole thing by the FBI (just like the "plot" to kidnap the governor of Michigan, which was concocted entirely by the FBI to rope in a few targeted individuals), they tend to look for more..."impressionable"...individuals to work with.