River didn't like feeling like this, feeling vulnerable, especially in front of the Doctor. But it was difficult for her to feel any other way at this moment. She felt as though she were laying her soul bare, which she was. The better part of her knew she shouldn't be doing this, that it went against absolutely everything that Time Travelers like the Doctor and herself lived by. And considering their timelines were inverse to each other, there was even more incentive to adhere to not giving out spoilers.
There was a moment where she thought herself insane for even doing this, for giving away this extremely important plot development. But it was better this way, him learning this from her and not a television show, right? It had to be. And in retrospect, she perhaps should've told Amy about having been her daughter before she'd seen that episode. But again, River was having a hard time throwing away the rules and being candid about herself. After all, she had spent years living in reverse from the Doctor and her parents that she'd kept her mouth shut about a great many things. Perhaps that's why the Doctor had given her that journal in the first place, it would allow them to compare notes and discover where they were on their timelines without spoiling anything. It was now that she missed adhering to those rules the most.
Oh the Doctor was spot on with thinking this was exactly like those times when he'd questioned her on who she was, badgering her with so many questions and a large dose of distrust. At least this time he wasn't looking at her with distrust. Had he given her that look, she didn't think she could get out what she needed to say. She hated those days when he had no clue who she was. The one that had hurt the worst was when she'd met his Tenth regeneration in the Library. He had absolutely no recognition of her, and it didn't take her long to realize that was the first time he'd seen her. But now, they were here, and she was telling him exactly who she was and what she had done.
Even as she related the tale, she braced herself for the yelling, the lashing out. She wasn't exactly sure what part he'd take the most offense to. Perhaps it would be her being kidnapped and experimented on. Or the fact she'd tried to kill him. Or would it be that she'd given up her regenerations for him? It was hard to say until she saw the way he reacted. Despite all of that, she knew that he would have the hardest time taking all of these spoilers. River wasn't one to lay things on lightly when she was free to talk about them. Well, not usually anyway. And she had an inkling that the Doctor was taking notes to try and change what had happened on Demon's Run. She didn't blame him for that, she'd like to change it herself if she could.