Sheesh, this MC is a moron. The moment you're in the dungeon, I would've gone and killed that fellow and his party, because he was obviously threatening you (and probably plotting something), so I would've killed him, just to be safe. Not like anyone could find out why they died. He's going to have to deal with them later on anyways, so might as well deal with them from the get-go, but noo, gotta be the little loser that he is and keep on delaying for long enough that enough damage is done and that he has "no other choice" because growing up and tossing the stupid naive morality out the window is too hard for our little brat.