Well, Chad and Patrick have seen RM before in the house during Halloween and they ran away when they saw him outside the window.
Murphy is known for ruining series and last night's episode was in fact, written by him. Which would explain the how awful it was.
As for being OOC, I still think it was in character for Tate to do that. Afterall, he is a psychopath. I think a lot of people forget that Tate is pretty darn crazy. He was crazy before we found out he shot up his whole school--he has never been a good person. I'm actually very worried for Violet because he is a psychopath.