This is just a short one shot of what would happen if Amy and the Doctor had a conversation about Rose. It's just meant to show how scared he is for Amelia. Takes place right after Amy loses Rory the first time.
The Doctor was alone in the Tardis. Amy had retired to bed for the evening shortly after Rory ceased to exist. The Doctor swept his hand over the bright flickering lights, listening to the steady thrum of the Tardis in motion. He suddenly stopped his circle around the console and twirled around to lean on it. The Doctor looked above him at the various electric currents zapping through the ceiling. Every speck of brightness was calculations made by the Tardis about the endless planets and times he had and had yet to visit. He watched as his trip to Venice with Amy and Rory flew across before taking a sharp right and disappearing to another room.
He smiled at the memory of Amelia's account of Rory's fight with the Vampire fish monster, and almost immediately recalled the fact that there would be no more accounts of Rory and his bravery. In fact no more Rory period because as far as history was concerned Rory never happened. The Doctor was the only one to remember his fallen comrade. Amy lacked the ability it seemed to fight time. It really wasn't surprising, but at the same time it was. Rory had loved Amelia so much, and now just as she was coming around Rory ceased to exist and it was his fault. The Doctor recalled a conversation he had with Mr. Williams while Amelia was with the Vampire Fish.
The two stood anxiously awaiting Amelia in the courtyard. The Doctor's light shone brightly in the darkness. Rory was twitching, looking about like a vampire was going to pop out at any moment.
"That's what vampires do, right? They drink your blood and replace it with their own." Rory had suddenly turned serious.
"Yeah, except these people haven't just had their blood taken, but all the water in their entire bodies." The Doctor rambled on just as an eccentric college professor would at a lecture. The deadly situation was unknown to the alien, having been in so many before.
"Why did they die? Why aren't they like the girls in the school?" Rory was persistent, and it seems as though the Doctor had finally caught on to Rory's concern.
" Maybe not everyone survives the process."
"You know what's dangerous about you? It's not that you make people take risks, it's that you make them want to impress you. You make it so they don't want to let you down. You have no idea how dangerous you make people to themselves when you're around."
The truth was sudden and absolutely true. It struck him in an instant and seized the part of his mind that refused to believe the notion. Why was it that this nervous, unsteady nurse had to be the one to point out this flaw. THE flaw, he caused in all of his companions. That desire he produced that made all of them risk everything just for him, only to achieve that goal and disappear forever. So many times it had happened. Everyone tried to keep up, not caring the consequences, only realizing their mistake of trying too hard when it was too late.
Donna Noble, oh how he failed her. In more ways than one Martha had been put in danger with her family. Sarah Jane and her son, his daughter, and even Captain Jack had all stuck their necks out for him and in one way or another some of them have died. A pain in one of his hearts caused a wince as the memory of Rose crossed his mind. That day on the beach, just after she had been rescued by her father and sealed in an alternate dimension, all his fault. He failed her.
"I failed her." The Doctor had unknowingly said that last bit out loud. Voiced in the room which Amelia Pond had just entered, looking for the raggedy man. Puzzled she tip toed up behind him, wondering who he was talking about. When his face was in view the expression broke her heart, and she frowned a little as she touched his shoulder lightly.
"Failed who?", she asked.
"Oh Amelia", the Doctor said warmly, building up a facade over his underlying sadness."What are you doing up?"
"Doctor who did you fail?"
The Doctor waved his hand impassively as if to brush her concern aside."Nothing, no one just never mind about that. You have to get to bed, lots to do tomorrow. There's the waves of the hermainion oceans, and the star surfers from the Sudistian Galaxy, you really must sleep." The Doctor tried to usher her out to the bedrooms, but Amy suddenly turned around hands on her hips.
"Doctor, who did you fail?"
The doctor sighed seeing that she wasn't going to give up. He walked around to the type writer pressing random buttons to avoid eye contact."Someone I knew very well", he vaguely mentioned.
"Did she travel with you?"
"Yes."
"What happened?" Amy walked over to him and they both leaned against the console like two friends having a normal conversation.
"She got trapped in another dimension. My fault entirely. I really", he paused."I really cared about her, and now she's gone. It's okay though, she's happy now."
Amy squinted at him, trying to deduce the multiple feelings that the Doctor was experiencing at the moment. He stared at her through the corner of his eyes, and when she suddenly backed off, he sighed in relief, but then tensed up with her next words.
"You loved her."
The Doctor turned to Amy."Yes, but I was different back then. I still care for her, but love is no longer a word that can describe my feelings for her." The Doctor pushed himself off of the console and walked to the edge of the plat form, holding on to the metal bar."But I didn't save her, that's the point. She needed me that day, and if it wasn't for her dad she'd be..." The Doctor closed his eyes and paused and then spun around to face Amy."Amelia I don't want anything to happen to you. I don't want to fail you." His eyes were pleading and Amy rushed to his wiry frame and hugged him. She let him hide in her hair as she tried to comfort him.
"You won't fail me, you never will. I won't allow it." The Doctor couldn't press down the laugh that emerged from him.
"That's not how it works." The two pulled away from each other."Everyone I care about gets hurt especially the ones I'm closest with. Rose, you and her are so alike in so many ways. I try so hard not to get close, but if I lost you I'd go mad."
"Oh Doctor", she said looking at him and moving so they were inches apart."I'm not going to become her." Amelia started to lean in a bit and the Doctor subconsciously did as well. The space was closing fast between them, and he knew that if they kissed she would become the new Rose. In this moment when one thinks they've achieved clarity, they do the one thing that foils their attempt at that goal being strived for. He paused and instead changed gears pulling her into a final hug. Sentiment in that way would lead to her undoing, and his as well. He had to keep her from getting too close.
"No you won't", he finally confirmed. When they pulled away the Doctor pretended not to see the hurt in her eyes from the rejection. He smiled warmly, and so did she. Each putting up a mask for the other. Amy couldn't help herself, and yawned into her arm. She glanced at the Doctor and they both laughed. He ushered her out the room to the door way."Time for bed", he pushed.
Amy smiled and turned to him."Good night Doctor", she smiled and walked away.
"Good night Amelia."
It was only later he realized his mistake that night. She had become the new Rose in the moment he pulled away. What he thought was the solution, actually sealed her fate. The same mistake he made with Rose, occurring again with Amelia. The problem wasn't getting too close, but not getting close enough. I love you. The words he never uttered to either of them, not once. Both he pushed to a friendly distance, and because of that they were both gone. The kiss almost shared between him and Amy would've saved her from the weeping angels. She would still be here if he only realized why he failed them all. The Doctor is the smartest man to ever live. He has no faults except one. Nothing unknown except for that one complicated, lovely, simple, hurtful, funny, complex, saddening thing, emotion.