Just a little warning if you do want to go the gun route i would suggest a shot gun over a pistol or rifle. The reason being if you miss with the pistol or rifle the velocity of the bullet will cause it to travel through walls and can possibly hit some one on the other side.
A few years ago in a town not to far from me a man was protecting his house from a robber with a 9mm pistol he missed with his first shot it went
through the wall and ended up hitting a little girl and killing her, he is now serving time for manslaughter. just a thought
But i digress any form of martial arts should suffice you in a CQC situation, i currently work with a guy who used to run a martial arts/MMA training
facility, he preaches the basics of self defense to his wife, kids, and co workers. foot, groin, face.
thank you and good day/night depending on your location in this universe.
p.s. i must admit i am a hypocrite lol i carry a pistol with me when im on the road for work but thats mostly because a shot gun is a little harder to