Yeah, it's stupid. He believes she knows where the cores are and won't tell him. So, she's threatening to kill herself before he can get that information but now, he's threatening to kill her with a gun for threatening to kill herself with a knife. Doesn't make much sense.
It would be more believable if she started to threaten him with the knife, then it's an odd stand-off between knife and gun. I just wanted her to just rush, stab him. Even if it meant she got shot.
So, are the no more laws because the punk broke a bunch of laws? If he's allowed to do that than the MC should easily be justified in just killing him. After all he'll just do it again without some other law enforcement. Can the MC just dispose of the body in a dungeon and then revert back to his old self even if his new form is now wanted for murder?