Why Can I Not Simply **Spoilers**

Okay, maybe this is a dumb question. But it’s legitimately one I’m wondering, considering the game does not shy away from violence in the slightest.

If my character has a gun equipped, why can they not just shoot Lum during the confrontation scene regarding Tangent’s Plague, considering there’s no one else to intervene? In fact, why can they not just kill Lum at any other point when they have the opportunity?

I wouldn’t even care about getting a game over for it and having to restart a new run, just let me do it once.