Authors note: This one is a lot more simple then my other fics. I was inspired by Dolphindreamer. I know this isn't quite what you suggested but this fic was born from your idea :)
I removed the part of the episode about the photo album just to make it simpler and just focus on the interaction between Red and Liz.
He stood in front of her, simply gazing down on her. There was no emotion on his face and he seemed to be almost waiting for something from her. And that's how they stayed for what seemed like minutes. She didn't know what to say, this man before her, this man had just brutally killed another man while she was in the same room. And yet he just stood there, a sense of calm about him.
"Lizzie." She blinked a few times, her brain slower than usual to process that her name had been said. "Lizzie it would be beneficial to your health if we left this place. No doubt the FBI is on their way."
"You killed him." Her voice sounded slightly slurred, as she struggled to get up from the wheel chair. "You didn't have to kill him… you're no better than he was…you're a monster." She assumed he would laugh and make a witty comment as she finally managed to stand and stare at him. But there still was no emotion on his face.
"Yes." That was the only answer he gave, and for some reason that shocked her. How easily he just agreed with her as he still stared at her intently.
"How can you live with that?" Her strength was slowly coming back and her voice held more force and accusation.
"By saving your life." He paused and looked around the room and then back to her. "I already told you before Lizzie, I have found I will do what is necessary to keep you alive."
He nodded as if to put an end to the conversation and gently took her arm, turning her towards the door and leading her outside. As they walked from the house, evening was upon them and Elizabeth couldn't help but think on what he said. He had already killed one man to save her life, and had come for her after being kidnapped. And then he killed her captor. Should she feel grateful? Or sickened that he killed so easily with no repercussion to his emotions? The most important thing that kept repeating in her mind was the way he had cared for her. The gentle way he had put her legs back in the wheel chair. The way he had said hello to her in a kind reassuring voice and told her she would be okay. And the way he had stroked the top of her head after he wheeled her away from the man who had hurt her.
These were not acts of a monster, and they certainly held sentiment. They showed he cared for her. Hell the man had killed people for her. He had stopped men from killing her. And with that thought she stopped walking, which caused Reddington to stop as well, his eye brow arched in a questioning way. She looked at the man who saved her; she would be dead now if not for him. The Stewmaker would have dumped her in those chemicals; he had drugged her and was going to watch her boil down into nothing while she was still alive.
Suddenly it all became real for her, she had almost died. She had barely been saved in time. She felt the tears start to form before they started running down her face as her body started to shake. Reddington's eyes softened faintly and he opened his mouth, what he wanted to say Elizabeth didn't know because she found herself moving towards him, burying her head in his chest as sobs began to rock her whole body. His arms came around her, holding her in a firm but comforting embrace. As she wept she felt a hand soothingly rub slow, small circles, on her back. She didn't know how long they both stood there, well into sundown, as she let her emotions sweep over her again and again.
After some time when she felt the tremors leave her body and her breathing slow back to a regular pace she noticed he had made soft shhing noises as he consoled her. As she was obviously coming back to her senses he had stopped rubbing her back and now he was just holding her.
"You're going to be alright Lizzie." His voice was muffled by her hair, yet she could distinguish a sadness tinted in his tone. "I know you're disappointed in me, or should I say revolted. You perceive me as a monster, and while I agree that I am I can guarantee that I have never been nor will I ever be what that man was."
The sadness was more prominent this time as he spoke to her. Had her judgment meant that much to him? And while she knew finding relief in his embrace should be wrong and inappropriate she couldn't help but feel safe. Reddington who had never treated her like the FBI did, nor lie to her like her husband. He always protected her, just like he said he would. And she found him a man she could almost trust. She knew their relationship would not be the same after this, and a small part of her was tired of fighting him every step of the way. Part of her just wanted to be held and looked after.
"You're not the same Red, The Stewmaker wouldn't have been here giving me a hug while I'm a crying mess. He wanted to cook me down the drain." She mumbled into his chest but she knew he heard her as he tenderly stroked her hair.
People approaching could be heard in the distant and she knew the FBI would be there any minute. She almost wanted to snort in hilarity at how late they were arriving. She pulled away from Reddington, straightening her clothes and hair before wiping her face of any trace she had cried. It wouldn't do for anyone to see she had broken down, and though she had more faith in Reddington then she had before she was not about to admit it to anyone, let alone have them know what had just happened. When she was done she saw him watching her in amusement and she looked at him challenging. "And what are you looking at? If I agree not to tell Cooper about the little shove you gave the Stewmaker, enabling him to fall to his demise then I would hope you don't breathe a word to anyone of what else took place here. "
Despite the menacing look she gave him he laughed cheerfully and shook his head. "You revealed a very personal and intimate part of you Lizzie, and I can promise you I won't share it with anyone. You may have your cold exterior to keep yourself safe and earn respect but you don't have to do that anymore." He smirked at her yet she saw affection shining in his eyes. "You have me now."