I have not watched the cafe shooting video(s) in depth but I'd say the armed guard's response seems more of a surprise or a rapid reaction rather than some LE or conditioned training.
I do not like to speculate or assume anything. More facts or details may be made public. It could be the security officer was a retired cop or had tactical training. The armed guard in the Daytona Beach FL area drug store event posted on
www.YouTube.com was a retired police officer.