I wasn't doing anything inhumane, but after the concert chapter it just sent me down a dark ending that I feel was undeserved. I have no idea how but it's a bummer because now I have to start over.
if you send him in the valley the first time, which at that point the player might not be aware of the implications, then you might inadvertly set yourself for the ruthless route. it's less about being nice and more never sending him to the valley.