In the teacher arc, fmc got a gun and gave it to the teacher. If she got one she could get another, MC should've gotten multiple with his tens of thousands of dollars USD equivalent and been armed, then he could've shot them because they're not allowed to kill him. Or at least tried. But mc has a case of author-induced retardation. In any case, his sisters death is his fault for not being armed despite being so rich he could buy them black market. A clean new black market 9mm costs about $2k in the US at most, in box with ammo. He got 50k the first video he shot with fmc.