Thank you for posting the video.
If I was was faced with such an attack, I'd be readty to die fighting, but fight to take one with me or leave a bloody mark, for evidence. At contact range, better to get closer aside then to turn and expose your back, and do the utmost to get back on feet when knocked down.
I don't carry because I don't have a CCW Permit. If I were to conceal carry I would practice with a holster and pistol, loading a cartridge proven since trenches of WW I: 45 ACP. 380s or 9MM seems effective for killing or maiming when you have the advantage of the element of surprise, but i want the best chance of stopping armed felons that surprised me or have already mortally shot me.
Without guns, what kind of knife would you carry? I usually carry a Benchmade folder or a handier fixed knife for urban carry. Hopefully, that and the years of karate/Hapkido base with jiujitsu training will help. When the situation calls for it, I have brought my handgun, that I have shot 1000s of rounds: better to explain then to fail to defend my loved ones.
"karate" is for when you're out of bullets (or have not yet presented your bullets) ...there're many delusional wishful thinking karate schools out there, by the way.