Ok so the guy in the video said:
A) nothing beats a shotgun.
B) a 45acp does considerably more tissue damage than a 22lr
C) the only way a 22 beats a 45 is if you miss with a 45, and can't manage accurate follow up shots.
You noticed that too eh?
The reason there are sooo many mouse gun defensive shootings, is cause there are so many mouse guns out there.
If all you got is a .22, .25, .32 or .380 then run it, but its not ideal.
The mechanisim of putting down a violent attacker quickly is this, in this order:
Central nervous system hit
Massive blood loss
Small caliber, and low velocity medium caliber rounds lack the chops to get this done quickly.
Sure you an very quickly riddle a target with .22 rounds with frightening accuracy... and chances are you will hit somthing vital, but what happens if you dont? Since you just squirted your 10 rounds of .22, now you are looking at a combat reload... not something you really want to get into as a civilian. 10/22 with a Bx25 you say? Ridonkulous, I say... if you go for a long arm, it should be a 556, 7.62x39, or big pistol caliber carbine, or a shotgun.
I agree with the school of thought that says run whatever you can shoot confidently and fire a rapid controled pair with.
And load said weapon with a expanding type round that offers the highest velocity for the caliber to ensure it actually opens up.
As the crackpot in the video said its all about training and practice... so why not learn to deliver rapid controled pairs of .38 spl, 9mm, .40, .357 mag or .45?
When faced with a violent encounter, decisive action and massive counter attack is what wins a fight. Medium high velocity rounds or large calibers is what you need, a katana or english broadsword to the .22's icepick if you will.
Me? FWIW, I'm one of those "velocity freaks" so 9mm+p or .40 with a hollow point big enough to mix a mai tai in, 5.56mm M193 out of an 18" barrel, 3" magnum 00 shells and stuff like that is where I put my faith. Physics is science... science is law.