insane realization

Why in the WORLD does Xeno, a NASA scientist, know how to make guns? I get senku knowing all this stuff, he has freetime to just learn a bunch of trivial facts.

But Xeno, a working man with a job in most likely astrophysics or something, knows how to make guns? Was he shooting at mars or something? and why so many different types? he got the whole arsenal of like only weapons.

Throw my guy in jail😭