She decided not to press the issue. She knew well she'd be ignoring any order to stay behind or not get involved or anything like that. She wasn't going to leave him to Lilith, even if somehow horribly he was ready and he killed her. She wasn't going to stand by and let him make the final run on his own. She deserved better than that or how exactly did he intend her to go on without him if it went bad. She had no intentions of doing any such thing. For all he said, for all the promises he made, Ruby knew Sam, it was very Winchester. Take all that lovely self saccrificing attitude and mix it with love and you got Sam trying to ditch her, trying to 'keep her safe'. Ruby decided then and there that if he tried any such thing she'd punch him, and dare anyone stop her. Weirdly though she expected Dean wouldn't have an issue with the concept much as he disliked her. He'd probably be in line behind her.
But Ruby would worry about that when it happened. For now, he was right, having each other really was enough. Them against the world. She kind of loved the idea. And what he said then. "No, no you're not" she told him firmly, "Because if it is you and me against the world then you can't go anywhere. Understand. Not without my backing. Because otherwise what you said wasn't true just now, and I need to believe I'm never going to be without you. You need to promise me, you and me, all the way" She knew that probably wasn't what he'd meant by the statement, but it was now and he would have to just suck it up and tell her what she needed to hear. That's how it went and thats all she would have. Anything else was unfair of him.
Meanwhile though she kissed, and teased, and messed with him, Because she could, because it was fun and because she was her. "We can't" she repeated softly, pressing herself against him, "Of course we can't. It'd be wrong, They'd wonder wouldn't they? They'd assume. Imagine it." She pressed the kiss, all the while pressing just softly against him, his arms wrapped around her, her teeth slid across his lip as she pulled back watching him, still with that same soft teasing smile as she spoke.