Sure, according to that picture yeah, you rightfully can. But suppose it’s all rhetoric. Suppose he had no weapon in his hand but is in your face threatening you?
There’s a youtube security vid of a robber threatening a cashier & thrusting his coat pocket at her. He turns for a moment & she grabs a gun and shoots him.
He goes down and when the police arrive he screams “I ain’t got nothing! I ain’t got nothing!”
Since the vid showed that the cashier believed she was threatened with deadly force, she was not charged.