Not an isolated incident. I’m convinced the only reason we don’t see more reports like this is it requires a low percentage event to meet with a low (but top) percentage of the gun owning public.

https://citizentv.co.ke/news/inayat-kassam-meet-the-52-year-old-hero-who-saved-lives-at-westgate-and-14-riverside-227173/

Inayat Kassam: Meet the 52-year-old hero who saved lives at Westgate and 14 Riverside
In a previous exclusive interview with Citizen TV, Mr. Kassam said he was at a shooting competition when his phone rang and when he answered, “the caller said, ‘Shots fired. We’re scared.’”

Mr. Kassam got into his car with fellow licensed firearm user – Peter Bonde – and off they sped towards Westgate Mall where they exchanged fire with criminals, fought side-by-side with Kenyan law enforcement, and led hundred of Kenyans trapped inside the mall to safety.

See also:
https://firearmusernetwork.com/ipsc-shooter-wins-fight/