And before someone dredges up the c**p that this justifies carrying firearms so people can defend themselves in such situations, this comes from a press article:

"Inside the store, a security guard who was a retired Buffalo police officer fired multiple shots, but a bullet that hit the gunman's bulletproof vest had no effect, the commissioner added.

The gunman then killed the guard before stalking through the store shooting other victims."

So an armed security guard, probably trained in the use of firearms was unable to incapacitate the gunman. That tears the NRA argument that people need to be armed to protect themselves to pieces.