She was an unraveling mystery.

No matter how many nights he spent lying by her side, she was still unraveling.

Sometimes, nights were his favourite time to be with her. She was quiet, for one thing - a rare achievement for Cristina. Though her razor tongue and wit were two the things he loved most about her, sometimes he found them exhausting. Some days she would fight him at every turn; her surrender came in the evenings.

With her small back pressed against his much larger frame, her body was at complete ease when he encircled her. She might not trust him as much as he would have liked during the daytime, but darkness casts a spell on her. At night, he knows he has her. Her body betrays her, as do her nighttime noises, when she melts into his arms. The mental picture of Cristina's horror if she realized she sighed contentedly as she settled into sleep made Burke smile wryly.

He is welcoming her into his home – their home, he corrects himself – as much as he can. He played his trumpet after dinner that night. It was a familiar ritual for him. His hands mastered surgical tools during the daytime, and his instrument at night. He could see her in his peripheral vision, as he lifted the mouthpiece to his lips. His lips effortlessly pressed tightly together from years of practice, as he began, as always, with a C Major arpeggio.

He closed his eyes to block out the image of her raised eyebrows, as she glanced up from her book. This is what it means to live with him, and he's comfortable enough to show her, though she may still be struggling.

He knows if he pushes too hard, she may push him away – maybe permanently. So he's letting her explore her surroundings, and he has to have faith that soon, she'll let her quirks, her habits and hobbies emerge.

Though perhaps she already was, he mused that night, as he walked into the bedroom. She was already dozing, quite a feat given the four empty coffee mugs on the night stand. Burke automatically gathered them up, and winced as he noticed the water rings they left behind. He swiftly washed them up, then went back into the bedroom.

That night, the sixth night since she officially moved in with him, felt routine. He cooked, he played his trumpet. He did fifty push-ups, he did the dishes, he brushed his teeth. He ran a hand over his hair and considered when he could next get a haircut. He changed into his pyjamas, propped himself against the bed head, and opened his book.

But the best part of his new routine came when he placed the bookmark back in, and switched the lamp off. She was dozing, her body in a permanent state of exhaustion due to life as an intern, but she never fell asleep until he was holding her. So her body moved unconsciously into his arms as he moved down under the covers, to envelop her.

Spooning against Cristina, Burke was contemplating his new unraveling mystery, the contradiction that she is in his life. She is compassionate to her friends, and increasingly warm towards Burke, but ruthlessly competitive. She will step on anyone to get ahead at Seattle Grace. This quality means she will make a formidable surgeon. As Burke's eyelids began to fall, he could only hope the same passion that consumed her as surgeon would soon be the same passion she held for him.

The buzzing of an alarm permeated his conscience a mercilessly short time later. He groaned as Cristina automatically moved to get out of bed, and tightened his hold around her waist. "Hit the snooze button," he murmured, burying his head in her thick mane.

"Can't," she complained, wriggling slightly, trying to escape his firm grip on her. "Or Alex will steal all the good patients on pre-rounds. Jackass."

"Please don't mention Karev again when we're in bed together."

"Gross. Seriously. Now let me go." He answered by pressing against her more tightly. He sensed her relenting slightly, and she shifted in his arms so she was facing him. He opened his eyes slightly, and found her brown gaze meeting his. That was his undoing. He pressed lips against her forehead, and reluctantly loosened his grip.

She left while he was still in the shower. She was still avoiding driving into work with him, even though it was now common knowledge that they were living together.

He didn't see her in the morning, as he was up to his elbows in innards for a good portion of the morning on a particularly messy surgery. O'Malley impressed him with his growing skill, and he made sure he mentioned it to the Chief.

Glancing at the board on his way to lunch, he saw that she was in surgery with Shepherd.

He wondered when his days started to revolve around her – glancing her at a distance, sharing a smile, bantering, a stolen kiss. He is one of the foremost cardiothoracic surgeons in the country, and he lived for his surgeries. They used to give him his greatest rush, and sense of achievement. He marveled that brushing hands with this crazy woman as he guided her through surgery could distract him from that, and take him to an even higher place.

He kept an impassive face as he did a consult for Stevens, and performed a double bypass. He was calm and collected. In complete control one moment, as he closed the man's chest. He was spiraling out of control the next moment when he saw she was still in surgery. The sun was well past setting, and he was on call that night. With the hospital in a rare lull, he went into an on-call room.

His body and mind had only just surrendered to sleep when she barged into the room, locked the door and exclaimed, "Burke!"

He groggily raised his head from the pillow, rubbing his eyes. "Mmm?"

"Thirteen hours in brain surgery! And Shepherd let me close! And damn I was good, that man's head won't fall open, not with me as his surgeon…"

Burke smirked. He enjoys her post-surgery high. She was always buzzing, but her underlying tiredness brought out a quirky sense of humour. Once the adrenaline wore off, she was always exhausted. He shifted to allow her room to sleep beside him, if she wanted to.

"Well, the Chief will be glad to hear the patient's head won't fall open. That's one less lawsuit to deal with."

She grinned, and sat on the bed beside him. He studied her face. She was always deeply satisfied after surgery, and it's the closest he's ever seen her to happy. It was something that came from the inside out. He reached up and tangled his fingers in her curls, silently wishing that he'll learn how to bring her that happiness. He was glad she'd sought him out to share her excitement with him.

"Just how tired are you?" she asked.

He propped himself up on his elbows, recognizing the look in her eye. "I guess it depends on what you've got in mind…"

And in a flat second she was underneath him, their limbs intertwined. She laughed as his mouth explored her neck, and tugged his scrubs over his head. As his tongue slipped inside her mouth, a moan escaped the back of her throat. This is another time when Burke knows he has her completely. And the rest, he hopes, will follow.