A/N: So I couldn't get this alternate version of my World's Collide universe out of my head. This is a what-if take to Connor not making it back to Sarah's apartment before she left for Mexico City. I'm thinking this may be around fifteen chapters in total. Please read, enjoy, comment.

This World Sure Is Small

This was a hell of a first day.

Connor eyed the open door to the practice lab with nervous anticipation. Surviving a train crash to then be put face to face with the woman who had torn his heart to shreds... well that was an entirely different kind of train wreck. His heart was still lurching in a funny rhythm, one he was all too familiar with, one that had only been evoked by one person.

He hated it.

He thought he had gotten over her.

Christ, his hands were shaking. Two tons of twisting steel and screaming people had done very little to his nerves. Yet, a five-foot-seven woman who weighed in at a buck-twenty soaking wet had him ready to crawl the damn walls. Connor gritted his teeth and rocked on his heels as he tried to get ahold of himself.

"You are?" He hadn't bothered to look at the person lingering in his periphery. His focus had been on his patient, but he wished he had looked. The moment her voice hit his ears he had damn near pressed the scalpel he'd been wielding into his patient's throat. By some miracle, he merely froze and swung the sharp implement back to the tray as he looked at her.

"Sarah Reese, fourth-year med student."

And there she was. Same curly hair, now tied into a sloppy bun. Same big brown eyes that he could drown in, staring at him in a strange mix of determination and uncertainty. Connor didn't know what she had to be uncertain about. She had left him. A million and one questions spilled through his thoughts at the sight of her, but this wasn't the time.

"Can you do a cordis in the groin?" He had asked, processing her title as he did so. She shouldn't be a medical student. She should be in her third year of residency.

"Mm-hmm." She nodded, flustered.

Connor had nearly arched a brow at her. It had been almost six years since he had last seen her, but one thing was still certain - he could still read her like a damn book. She knew how to do a cordis he had no doubt about that, he didn't think she had ever actually performed it on a breathing person before because he hadn't missed the nervous glint in her eyes as she glanced at their patient.

But she was stubborn. His girl always had been, and his presence was doing nothing for her nerves. A strange note of satisfaction pierced him at the knowledge that Sarah was just as affected by him as he was by her.

She missed the vein, and he took over.

Connor hadn't missed the faint haze of mortification she cast to the floor and all he wanted to do was reassure her, but his patient was flatlining and she disappeared on him before he could.

She disappeared on him. Sarah was good at that.

If he were honest the only reason, he had decided to stitch himself up in the ED was because he knew that she was flitting around nearby. He wanted her attention. He had wanted her to come over. He had gotten April and Sarah had continued to avoid him.

His jaw twitched with latent anger and then he caught sight of her bun. His feet moved without his permission and the dumbest observation fell from his mouth because these were not the words he wanted to say, "Central line. Can't tell you how many times I missed before I finally got it."

He watched her pause for the briefest of seconds, but she didn't look at him. Her full concentration on the training dummy. He wished he could say her diligence was because of her work ethic, but Connor knew in his bones that Sarah was trying to avoid him.

"I know how to do it. I just couldn't do it in there." Sarah didn't bother to hide her agitation as she sent the needle home.

"It takes practice that's all," Connor replied stoutly, she never did have any patience.

"I'm fine with him." She tossed the needle aside, looking at him for the first time, "I never miss."

And he had to bite back his instinctive response to her frustration. She always did have to be perfect at everything, "Yeah, he's the ideal patient. You can't hurt him and his life's not hanging in the balance."

"If this rotation weren't a requirement, I wouldn't be here," Sarah grumbled.

I wouldn't be near you, is what he heard.

For the first time, Connor wondered how much of that frustration she was feeling had to do with them meeting each other again. Did she hate him that much?

"Where would you be?" He pressed.

Where have you been? Is really what he wanted to know.

"I'm a lab person." Sarah lamented, holding his gaze and he saw something that looked like an apology there.

"Pathology." It wasn't a question and she heard it too.

Sarah seemed to take his statement as a challenge as she defensively threw back, "Maybe."

"Yeah." Connor breathed, feeling his pulse race as he stepped closer. How did she do this to him? "Every med student once they start dealing with patients thinks they'll do better in pathology. I did."

Sarah tilted her chin up at his words because she remembered that. She remembered how he'd come to her place after a shift in the hospital feeling like the most incapable idiot. How tense and annoyed he would be, and she would have to pull out all the stops to get him to talk to her – get him to breathe and be sane. He had lost count of how many of those nights had ended in her bed, losing himself in her. Thanking God that he had her to turn to.

She remembered that too. Connor could see it, "Sarah -"

"I should go." She said abruptly, swallowing tightly and yanking her gloves off so she wouldn't have to look at him anymore.

Connor wasn't ready for her to run away from him again. Not yet, "Are we really not going to talk about it?"

"Is there something to talk about?" Sarah whispered and her eyes were on him again. Those big brown eyes of hers that could make him do anything – staring at him with a strange desperation that he didn't understand.

"You left," Connor whispered.

Sarah huffed, "And I came back. You didn't want to see me, remember?"

"What did you expect?" He demanded, feeling every inch as furious as he did six years ago, "You could have come to me about the baby, Sarah. You didn't. You decided for both of us what was going to happen and didn't bother to inform me. I had to hear about it from Alex. Did you expect me to be happy about it?"

"No." Sarah choked out, a sheen of tears coating those eyes, but she was strong. She didn't let them fall, "No - you know what? It's in the past, Connor. We can't change that now. And I do need to go."

"Fine then." Connor said bitterly, standing aside, "Go. It's what you're good at."

Sarah stared at him and for a moment he thought she would slap him. Instead, she bowed her head and brushed past him.

Turning only once to murmur, "I'm glad you're okay, Connor."

All he wanted to do was follow her. This wasn't how this conversation was supposed to go.

It wasn't until she was out of sight that he cursed softly and charged after her. Six years later and she still had him wrapped around her damn finger. He didn't find her right away and when he did, she was boarding a bus. He wanted to pull his hair out as old protective instincts rushed back to him. What the hell was she thinking taking the bus this late?

He raced across the parking lot but was too late. The bus pulled from the curb and was heading for the intersection. Connor swore he'd find her again in the morning.

Sarah climbed the stairs to her apartment sluggishly. Her hand rubbed over her chest and the tight pressure that wouldn't go away. Pressure that had slammed into her the moment she had heard his voice in the ED.

Connor was here.

At once her heart leapt with joy while her stomach filled with dread.

Connor was here.

She slotted her key into the lock and pressed inside with quiet care. It was all for not it seemed as she placed her bag by the door and she was greeted with a loud and cheerful, "Mommy!"

Sarah smiled faintly and turned in time to catch her son as he barreled into her legs, "Hi, baby. What are you doing up? It is far past your bedtime."

"Nana Schuler said I could." Big blue eyes beamed at her as he was picked up and tucked on her hip, "I wanted to show you what we did in school."

"Oh?" Sarah queried as she indulged him, "What did you do in school today?"

"We played a parachute game. Everyone had to hold onto the edges of this big parachute. And it was really colorful, and we took turns running underneath."

Sarah nodded as she listened to him babble. Her elderly neighbor stood from the couch with a fond smile as she watched the pair. She waved good night to Sarah, knowing the routine the mother and son before her had well. Sarah would cross the hall to hers once she got Callum settled.

Sarah slipped her shoes off once they crossed into the bedroom and she slid him under the covers with practice ease before curling around him. Callum yawned, but fought his tiredness as he asked her, "Did you get to save people today, Mommy?"

Sarah paused as she thought back to the little girl, she had done CPR on. Rachel. She hadn't been much older than Callum. Her arms tightened around her boy, "Yeah, I did. I got to help save a little girl."

Callum's eyes widened, "Really?"

Sarah nodded and smiled sadly as she brushed his dark hair out of his eyes, "Really. You can ask me about it in the morning because it's time for big boys to go to sleep."

"But Mommy!"

"No, buts, just snores." Sarah responded seamlessly as he scowled and she smiled, "We'll have to get you a haircut this weekend too."

The heavy sigh that came from her son was more amusing than anything. Sarah swore he was going to be a moody teenager when he got older. She pressed her lips to his temple as he cuddled closer to her, "Mommy?"

"Yeah, baby."

"Do you think Daddy saved people today?" Callum whispered.

Sarah nearly jolted at the question. Did her son have some weird six sense that Connor was nearby? She was quiet for a long minute, "Yeah, I think he did."

"Can we look at the book again tomorrow?" He asked.

The amount of hesitation in his voice nearly broke her heart, "Of course, baby. Anytime you want. Now shut your eyes. It's time to go to sleep."

Sarah stilled as Callum followed her instructions. It wasn't but a few minutes before his breathing evened out and he was fast asleep. She envied him. She hadn't been able to sleep like that in a long time. Her eyes drifted to the shelf in the corner of the room where the book Callum wanted lay. It was a scrapbook that Sarah had put together. Of her and Connor. Mostly of Connor – she wanted Callum to know who his father was. He asked about him more and more of late.

It had become obvious in the few minutes that she and Connor had spoken that he hadn't received any of her letters to him. He still didn't know he had a son. Her stomach flipped in dismay.

How was she supposed to tell him?