Weapon manipulation skills are needed. Blind field stripping, maybe not but it is useful.
I don't care who you are if your gun goes click instead of bang you are gonna look at it. It may just be a nanosecond as you clear it or change mags but you will look at it. The trick is quick looks.
Tactics will aid you in having time to perform the necessary drill. Remember get to cover.
There was a Dallas, TX officer killed in a shootout during the 1970's because when he went to reload his 1911 the slide would not go back in battery and the BG walked up and killed him. The slide lock spring had broken and he just made sure and pushed it down manually during quals, but forgot about the broken spring in the shootout.
We must also remember that a gun is only part of the solution, you may need unarmed self defense skills. I know somebody is gonna say "I am 62 years old I am not fighting with anybody" And if you gun malfunctions, you drop it, run out of ammo? Thats kinda like the definition of a POW-Hoping the guy you were just trying to kill has mercy on you.
My rifle and pistol are tools, I am the weapon.