"I've never said that. Ever. I'm saying that killing him should not the driving force in your life," he snapped back. "This isn't even about shagging anymore, Severus. This is about why you want to live. Has your life any purpose other than killing him? Anything?"
Regulus stopped, because he knew this was a lost cause. Severus didn't want to fight a war. He wanted to murder the Dark Lord. They were two very different things.
"What if I concede on this point? What if I go along? What about Potter?" he asked. "You never answered me about that, and don't play dumb, Severus. It doesn't become you."