Providing you and your loved ones are not threatened and he's not acting like he's going to shoot anyone else, stay calm have your hand on your weapon and be the best witness possible.
If it changes to a robbery-murder then do what you have to do to protect yourself and loved ones. Your statement to the police should be, "I was in fear for my life."
If it changes to a robbery-murder then do what you have to do to protect yourself and loved ones. Your statement to the police should be, "I was in fear for my life."