What would you tell 911 though? "Upset guy with gun at the convenience store" seems like a recipe for disaster.retired cop here.
So feel free to ignore my old man advise.
But RETREAT to where you were and CALL 9/11
Then any action you take makes you at least a better good guy.
And you do know most 'choke & pukes' 'shop & robs' have cameras.
So whatever you did ,or did not was likely recorded.
Also note ,not inconceivable there was a patrol officer outside looking in !.
That should pucker your butt !.