Your account of the events is wildly inaccurate based on the written OKC police statement and the KOCO TV reporting.
All three people involved were CLEET trained and certified, and one of the "good guys" was a reserve deputy. Nobody ran out of the restaurant to get a gun. The shooter fired into the restaurant and ran out, where he was ordered to put down his weapon, but instead tried to shoot the other two who had armed themselves and saw him come out of the restaurant holding a gun.
Now ask a relevant question, like what would you do if you had heard shots while you are in the parking lot, and a person came out of the restaurant and aimed a gun at you? You are LEO trained.

__________________
Science plus Art