This is post "Crash Into Me, Part II." If a "simple" storyline were an option, this is what I would go with.

He found Rose the next day, preparing an OR for one of Dr. Hahn's surgeries. "There you are," he said by way of greeting.

"Here I am," she agreed. "Good morning."

"Good morning," Derek repeated, smiling, as he leaned against the doorway. As if realizing what he was doing, he quickly dropped the smile and stood up straight, shoving his hands in his pocket. "I'm kind of, sort of waiting for someone," he said. "It was very unprofessional what I did yesterday. I want to apologize; I shouldn't have done that."

"It's fine, Dr. Shepard," Rose said, closing the cupboard she'd been working in. "I even enjoyed it. If you're waiting for someone, though, I won't stand in your way. I'm sure she's very special."

"She is," Derek said, finding that it was true as he said it. "I've been horrible to her and she's trying. The thing is, I've been blaming her for everything that's happened, and it's not her, not really. I should be really good at this, but I'm not," he said, "I'm an imperfect person."

Rose smiled. "It happens to the best of us."

"Yes," Derek said, "well, I'm sure I'll see you around Rose."

"Good bye, Derek," she said, turning back to her work. "Derek," she said, not looking at him.

Derek stopped. "Yes?"

"Meredith Grey is a very lucky person," she said, "don't screw it up."

"I won't," Derek promised, "thanks, Rose." She nodded and continued working.

Derek left the room. Its six o'clock, Derek thought, where would Meredith be. Rounds, he decided, and took off looking for her. He found her outside a patient's room, talking to her interns about protocol. Damn, now was not the place and time to have the conversation he wanted to have with Meredith Grey.

"Is there something you needed, Dr. Shepard," her voice broke through his thoughts.

"What?"

"Is there something that you need," she asked again.

"You," he said, without thinking. Damn, he thought, that was not good. She was smiling though, so it couldn't be that bad.

She turned to her interns. "Why don't you guys spend some time in the clinic this morning," Meredith said, "I'll come get you soon." George looked like he was going to put up a fight, but went with the others anyway. Derek took her hand in his and led her to the nearest on-call room.

"You don't have to explain," Meredith said, quickly, after Derek shut the door.

"Yes, I do," he said.

"Look, you kissed someone before I told you I didn't want you dating anyone else," Meredith said, "I'm not going to hold it against you. Don't worry about it."

"I kissed Rose," Derek confirmed, "and then told her I was waiting for someone." Meredith's eyes went big as Derek talked. "And I am waiting," he continued, "and I don't want to date anyone else. I am an ass. I get that now. I'm sorry I put you through all of this crap. I'm sorry I chose Addison. I'm just, I'm sorry."

"Okay."

"Okay? You aren't going to yell?"

"Nope," Meredith said, smiling. "I have to go get my interns, but maybe we can get together later and talk some more."

"Talking is good," Derek agreed. Meredith nodded and started out of the room before stopping and flinging herself at Derek. Seconds later the impromptu kiss was over and Meredith had left the on-call room. Derek sat down abruptly on the nearest bed with a smile on her face. She was trying; she didn't want him to date anyone else. That was progress and he could live with that.

See? Simple. Simple never hurt anyone. I can't imagine Derek falling for Rose just like that. And that's what it seems like: one second Meredith is the love of his life and the next he's getting goo-goo eyed over Rose. Sort of makes you feel bad for Addison when Derek started ignoring her. So, maybe Meredith isn't the problem, maybe it's Derek. Anyway, I hope you enjoyed my little one-shot. Thanks for reading.