"My baby sister," Oliver clarifies. He's abandoned his drink to put his hands in his jacket pockets, fingers working open and closed as though wanting something to clutch and a target to point at.

He has no room at the moment to appreciate that Derek looks upset about the revelation. He only wants to leave before he says something that can't be taken back. As angry as he is, Oliver knows that he's being a touch irrational-- but that doesn't stop him from feeling it all, and for five years his reaction to an overload of emotion had been to shut it down, or lash out if he couldn't.

Neither is an option right now.

"I'm going to leave before I do something I shouldn't," he tells Derek, chair making a scraping sound as he stands.