A/N update: it was brought to my attention that the term "fixit" may not quite fit the story perfectly. The first time I watched the episode, it took me a little while to figure out that River was the one who had to blink, so maybe this is just clarifying? Or in between? Uhm, I'm not really sure. Maybe it'll help make sense of the ending if it confused someone. But the scene was so fast that it was really easy to miss parts of what was going on. Sorry if "fixit" causes any confusion~
There was nothing she could do besides stand there and watch as her husband's hearts broke. But the pain on her mother's face was what spurred her next actions. How could she be doing this? She was telling her husband to shut up while her mother sacrificed herself to an Angel. This just felt wrong, but she knew it's what Amy wanted. After seeing her father die at Winter Quay just happy to see Amy again River just knew that she couldn't make him go through that when they couldn't create a paradox. She walked forward when Amy said her name, and took her hand. While it wasn't spoken, she knew what this meant. Yes, it was a goodbye, a mother expressing her love to her only child, but it was also something more. She kissed her mother's hand to signify that she most definitely understood what she had to do. The Doctor was pleading, and that broke her hearts. He would only ever plead when he was too desperate for anything else, and here he was, losing his best friend. Amy was still staring at the Angel intently, and River could see the hatred and the guilt on her mother's face. Understandably. Leaving your best friend forever, living in a paradox-muddled city where he couldn't ever see you because an Angel had snatched the man you loved away from you... Well, River was just about crying then. That's when Amy did it.
"Raggedy man..." She whirled, blocking the Doctor's view of the Angel so he wouldn't be able to stop it. "Goodbye."
River blinked.