Your suggestions of swimming away or taking on the leader in all out attack with your daughter by your side , may well be viable solutions depending upon the timing and dynamics of the confrontation!
If you are on miles of deserted beach front , late at night , as my friend was , where are you going to swim to ? The punks will be entertained and will have a beer party walking along the beach until you decide to come ashore exhausted!
You have to assess the chances of distance and timing ! In my friend's case , he knew that the highway was within reach by his daughter 's dash to safety and call for help ! [ cell phone in the car ] ! Better would have been a portable cell phone with a 911 speed dial , mated to a 1911 colt .45 !
As David says, the real weapon is the mind , the gun or any means you have to fight with, are simply an extension of the mind .Yet you must fight smart to survive , and you must create the impression that you are worse than they are if they decide to take you on , and you must believe that you will be or you will be lost !
Unfortunately , all the dan ranks in the world , private lessons from Nakahodo sensei or other high ranking Okinawan master , ability to break baseball bats with your shin etc. , won't do you much good against superior numbers and weapons and drunken punks ! That is why the handgun is called the "great equalizer" -and the punks knew my friend was about to blow them away , that's why they desisted from their nefarious intent !
I know this doesn't square well with the lotus eaters gracing this website , but unless you are well schooled in the principle of "force continuum" you will forever be nothing but "white bread" …and , as I have said before, be sure to buy an extra long "black belt" , so that it will fit nicely around your casket when they will use it to lower your ass into the ground !