[It's all starting to come together now. Ren invited Rey to the Supremacy, in hopes of turning her. Snoke most likely wanted to kill her and Ren couldn't stand the thought of losing some piece of trash, so he turned against his master and betrayed the First Order.

Only the girl wouldn't join him, but couldn't kill him either, and left to join the Resistance once more.]

You betrayed Snoke, you betrayed the entire First Order for some scavenger. [The anger and loathing is apparent in his voice. Of course, the cracks forming on the walls around him is a clear sign of his negative emotions as well.]

Why. And don't tell me because you wanted another ally with the Force, I know it's more than just that.