Headless monks believes that their existence continues because their minds and bodies are connected unbreakably with the use of soul. It's soul witch made person before death that in their case didn't wandered off what presumably happened to other unfortunate beings and acted like a glue of sort. So River had quite hard task in front of herself. She needed to find her soul and use it to link her mind (trapped in Dalek at the moment) to a new, never used body. She was sure that she's got better chances at building TARDIS from vacuum cleaner and custard.
- That's your life Melody Pond. Always skating on a thin ice. Thanks goods you love it or otherwise you will have been done with yourself ages ago.
"Body placed in vault." Now she needed to visit headless monks. And understand. Jack was busy setting up lab full of things from future and past from all around the universe. She, on the other hand had to start her way toward her redemption.
Having knowledge of religion and theory of what you are planning to do isn't enough. She knew that even before she left Library data core. Now she has to face in her opinion the scariest thing in the universe. Depths of her own mind and all demons inside it. Understanding yourself is neither nice nor easy. Especially with past like hers but now it was her only chance to get that soul back. She has to pray, hypnotize herself and meditate. Yes, meditate inside Dalek – who has a tendency of being real jerk at those times. But she has to go through that to make sure that her soul will be present at the time of linking. Because apparently you can't put a soul inside of a box but you might try to summon it when needed.
She wasn't sure how long she's been there. It didn't matter. She travelled through time and space, she could leave iron on every time she went out and never face consequences. So staying an hour, a month, a century… same difference the point was that she learned what she needed.
- Hello Jack. Is everything ready?
-As you wished Sir… Madame… neither? Have we met before?
-Few times even.
-So have we been formally introduced?
-More or less. There isn't always time to shake hands when you are running from a bullets or other things. But back to important stuff. Now it's time when you become the next Frankenstein. My life is in your hands. Literally. Let's do final check. You have to be sure you will give a clean shot. Precisely thirty seconds after I finish downloading. In the center of..
-I know where to point my gun! I'm not a blushing bride when it comes to them. You can even say I'm an expert. But are you sure…
-No, I'm not. I'm almost as uninformed as you at the moment. But we can't let that Dalek attack. Thirty seconds, no more, no less or I don't move completely.
-Ok. But whose body is it anyway?
-Mine if all will go according to the plan. You start the transfer with that button, you kill Dalek, and then start unfreezing body. In that exact order. Step after step. Then you will get your money. Vortex manipulator will move you automatically no matter what happens to me. Nothing else after that should worry you. I'm starting counting. Get in position.
How lucky that Daleks' voices are automatic. He couldn't hear her fear that way. Human voice without doubt wouldn't be able to work properly now. She was one bid bundle of nerves. Showing weakness in the moment like that would be more deadly than moving consciousness. At least for her pride. And she couldn't allow that. Not now.
Pain was way more intense than with others "tryouts" of off the world. But it stopped for a single moment and she was somewhere, somehow, at some moment in time and she was trying to reach something… or someone… only she has no idea what that was. And there was only darkness left. Darkness and cold. Does that mean that she's finally dead or that she's in a frozen body, or neither of above? Through silence like a knife scream cut out
-River!
Scream of a little girl and then… nothing. Silence. The creepiest kind of it. "Procedure completed". At that River takes deep breath, as deep as she could, as it was her first. And in a way it was. She has lungs again! And legs and arms and… yes… all of her crazy curly hair back in its place. Ladies, gentlemen and other humanoids River Song is back. And what a comeback it is. Now everything will be alright. She only needed to step into time line in good moment for her husband to catch her and everything will be… but that scream. Child scream. Was that illusion? Truth? Lie? An attempt to stop her? Or just long lost memory? Did she scream? Or was it Melody Pond? Perhaps it was some other unfortunate soul. Should she worry about that? Should she forget? Forget. Why does she has a feeling that she forget something… someone even?
-Oh get a grip River! – she yelled at herself.
-Doctor. You need to find Doctor and get back to the TARDIS. That should clean your head just right… and help you understand who screamed. No, wait. No. No scream. TARDIS, your Doctor, Amy and Rory. Nothing else matters to you.
So why does she feel like part of her has died, when she was supposed to reborn and be finally complete?