It is in fact amazingly difficult to actually shoot someone who is already at knifing distance who is intent on both cutting you and not getting shot. You can get past the muzzle of a gun very easily at melee distance, especially if all the other guy has is a rifle. And you only need one hand to keep control of your opponent’s gun if you have any modicum of skill. You don’t have to keep him from shooting it and in fact you probably won’t, but all you have to do is keep him from shooting it at you,

You will get shot by his buddies, sure, but not before you’ve stuck your pigsticker in his spleen.