Sam's explanation might have been confusing, but it truly was accurate. That was this place in a nutshell -- random fuckery with the knowledge that people actively enjoyed a television show of you being dragged through the dirt over and over again. He tried not to let himself get sensitive about it -- after all, there was Chuck's books back home and that was a nightmare. At least there were others to join in the nightmare with them this go around. Dean could see Ruby's face, painted with confusion above other things. A part of him felt a little sorry for her.
But that was a very small part and Dean didn't acknowledge that small voice that said 'poor Ruby'.
The fact that Dean knocked Sam would should have been the first clue that things might not go her way. Dean had gotten rid of the voice of reason amongst the two brothers -- the one who could potentially have the power to pull Dean back. But Dean didn't want that. He didn't want to be talked down from, he didn't want to listen to the rules -- even if Faith had even warned him.
It was blood lust...it was anticipation. Dean was ready to step forward and lunge at her before he was shoved back, the invisible force slamming him against the beam that Sam was once pinned against. Once. But he went only so far, compared to the likes of Abaddon -- Ruby wasn't really that strong. An angry, somewhat annoyed sound came from his chest as he took a step forward. He flipped the knife in his hand, getting ready for his own slice and going to open his mouth before slamming it shut and gritting his teeth the moment Ruby tried pushing him back again, and he did. The beam groaning once again from the force but Dean dug his heels in.
"What's wrong? Shootin' blanks? I think there's a pill for that." He winked a little, taking a step forward. More amused than anything else. The frustration on Ruby's face was clear to him and it almost made him laugh a little.