If you haven't viewed the "Semper fi" deleted scene, I recommend watching it. Google it. You won't regret it.

Basically after Elliot leaves he sends Olivia an envelope with his mini badge and a note that read "Semper fi" (Always Faithful). She keeps it clipped to her gun throughout the next couple seasons but it disappears after the Lewis abduction.

6. SemperFi - Always Faithful

"Fin! Mind if I leave this on the captain's desk?" Elliot held up the danish he picked up from the bakery down the street. He knew she wouldn't be in right now, but he wanted to drop it off anyway.

"Yeah, go ahead." Fin didn't look up from the game he was playing on his phone.

Elliot opened the office door and walked over to her desk. A few scattered case files laid strewn across the desk. A couple highlighters laid abandoned next to the report she must have been reading. He noticed a pack of sticky notes sitting at the corner of her desk, and he grabbed them. He'd leave her a quick note so she knew how food magically appeared on her desk.

He didn't see a pen so he opened the top drawer of the desk. He moved around a couple things and then stopped. His eye caught something hadn't seen in years. He lifted the small mini badge out of the drawer and held it in his palm. With the drawer sitting open he saw a yellow paper note tucked towards the back of the drawer. He carefully lifted it out, already knowing what it said.

Semper Fi, El

He lifted the badge up and rubbed it between his fingers, before he clenched his fist around it. This was the only thing he left her. A tiny badge and a cryptic note. For ten years this was all she had of him.

A voice came from the other side of the office. "Always faithful." Olivia leaned against her now closed office door.

"Sorry, I was looking for a pen." He lifted the mini badge, "I can't believe you kept this."

Olivia shrugged and walked towards her desk, "It was the only thing I had left of you."

"I figured you threw it away or buried it in a box somewhere after all this time." He sighed, "After the way I left…"

She held out her hand and he dropped the medal into her palm. "For a while it was." She turned it over and brushed her finger over the emblem. "It was actually in evidence storage for a long time. It took me a while to get it back."

"Evidence?" He looked up genuinely confused.

"Uh yeah." She put it carefully back into the drawer. "I had it clipped to my side arm for years." An embarrassed chuckle escaped her lips. "It was a way to keep you with me." Her voice tinged with sadness, "It was comforting, you know, like wherever you were you would still have my back."

Elliot felt like he couldn't swallow. At the time he wanted to make a clean break, figuring it would be the best for both of them. He sent the badge because he wanted her to know that she would always be a part of him. "How did it wind up in evidence?"

She shifted uncomfortably, and shut the drawer. Her eyes dropped. "Uh. Well. I had it clipped to my side arm, like always, and um, then William Lewis happened."

His stomach dropped.

"When they collected my side arm for evidence, the badge went with it." She turned away from him, but he caught her arm.

"Liv." He felt his eyes watering but tried to blink back the impending tears.

She lifted her warm brown eyes to his, and let him slide his hand down to hers, clasping it tightly. "I'm so sorry." He pulled her a little closer. "There are so many things I wish I could take back. So many things I wish I could redo."

She nodded, focusing on their now tangled fingers. "Thank you for sending it."

"Why? A reminder of my pathetic exit probably didn't help you."

"No," her voice was low. She pulled him towards her, wrapping him in a hug. He relished her nearness. "I needed to know you still cared about me." She sighed with discomfort, "And with Lewis," the name made Elliot's stomach turn. "It was hard for me to see him have not only my gun, but the only thing I had left of you."

Elliot didn't even try to hide the rising emotion. He pulled her into him tighter. "I wish I had been there."

"Me too," she admitted. "But it helped having it."

Elliot shook his head with self-deprecating anger. "A stupid mini badge. That's all I left you." His voice dropped with painful regret. Leaving her alone to deal with that monster was the worst thing he'd ever done.

She cupped his face, "It was enough." Her eyes teared up, "at the time it was everything."

He leaned into her cupped hands, pressing his eyes shut. "I'm so sorry. I know it doesn't change anything." A tiny badge was her everything. The thought demolished him.

"El, look at me." Her deep brown eyes bore into his, "you need to forgive yourself. I'm okay. I survived, and none of that was ever your fault."

He tried to protest, but she cut him off, "It's over, and I want to leave the past in the past."

She bit her lip, clearly thinking through something. She seemed nervous and that made him nervous. "I want," she struggled with the words. She started over, "I'm done holding on to everything that's holding me back."

Her eyes moved back and forth between his lips and his eyes. His breath caught. He didn't dare get his hopes up, but the intensity of her gaze made his heart pound in anticipation. His whole world stopped the moment her lips met his.

I might explore this story more later with some added length- watch out for that :)