N-S aren't "right" though. The derivations make a lot of good assumptions that breaks down in certain materials/situations.
What is right is its starting point on the conservation of momentum and energy. Then it makes certain assumptions about the stress-tensor which are not necessarily true. Meaning, you can derive the N-S from consv. of mass and E and a certain stress tensor (ST), but its not derived from a universal ST.
NS are a pretty good model for the underwater scenarios a Navy would be interested in, so I think they can be called "right" here. The fluids are regarded as "Newtonian" so the stress tensor model is good, and the density of the fluid is high enough that the continuum approximation is good. The largest source of error is likely the approximations made to model the turbulence, or in other words, reduce the computational complexity while also reducing accuracy.
His life doesn't have to be in danger to pull a gun!
1. He just has to justify that he had a reasonable fear for it.
2. Anyway he was protecting his property
In fact, he did a very honest thing: he brandished his gun. Which means he showed the would be criminals that he was packing.
Steps to shoot a would be assailant legally:
1. Show that you're packing
2. if the would be assailant doesn't leave, aim
3. if the would be assailant doesn't leave, shoot.
Its a very fast, but choreographed dance. The point of it being that you don't just get to shoot anyone right away, you have to give them a chance to bugger off. Which they did.
EDIT: I've never owned a gun and don't really want to own one (shooting is a lot of fun, but I don't want to be a gun owner). I might buy a .22 rifle (hardly relevant for this story)
Ironically, a black swan isn't really at all - just unknown. Which really is Taleb's point: black swans aren't as rare as they are priced to be.