You think an untrained person with a knife will be more effective than an untrained person with a Beretta?
Or you think it's easier to train a person to safely and effectively use a knife than a Beretta?
Either way, I disagree (and I have trained with knives and Berettas...)
The only way to(edited, explicit content)an attacker is CNS or hitting a major artery. If someone busted through my door I would take a 1' knife over any handgun for the following reasons. A. If someone busted through the door it would IMO very quickly turn into a struggle/fight and I don't think you would get many shots before the struggle/fight. And B. A knife would create far more damage then a handgun in that situation.
For a trained person a gun might be better but I've never trained with either weapon so I can't say for sure. As an untrained person I would take a knife over any gun in that situation.
Why would you prefer a gun?