If you’re going to go up against an armed attacker, catching them off-guard is usually the best thing to do. If they don’t see you coming, like if you’re about to hit them in the head with a chair, you’ll likely have the upper hand.
Even after that, you still might have some trouble, as you’ll see in the video below. If there weren’t multiple people willing to step in to get this suspect under control, he may have gotten away and may have been able to hurt someone before doing so.
This one gets messy, and bloody, so if you’re sensitive to that type of thing you may want to avoid the play button.