According to CNN, a married couple (Jerad Miller and Amanda Miller) under the impression that they were starting a revolution shot and killed cops in a pizza place, and then...
...ran to Walmart where Jerad Miller fired off one round and told people to get out... A shopper, identified as Joseph Wilcox, told his friend he was going to confront the suspects. "He was carrying a concealed weapon, and he immediately and heroically moved towards the position of Jerad Miller. Upon completing that action, he did not realize that Amanda Miller was with Jerad Miller," [Second Assistant Sheriff Kevin McMahill] told reporters. He continued: "As soon as he began to confront Jerad Miller with his firearm, Amanda Miller removed her firearm and shot him one time in the ribs area where he immediately collapsed." Wilcox, 31, "died attempting to protect others," Gillespie [a Walmart witness] said.
Amanda ended the revolution by killing her husband and herself.
As for the armed man she shot, he never made it near the status of hero. All he did was make a very bad situation worse by picturing himself in the NRA fiction of good guys with guns dealing with bad guys with guns. That fiction cost him his life. The reality is that a situation like this is always clouded by confusion. And throwing more guns into it only adds more danger to this confusion.