There were a lot of things Mark was good at ignoring.

The hum of the fluorescent lights in the hallway. The clunky way their science teacher pronounced "catalyst" like it had five syllables. The aggressive way Haechan clicked his pen during lectures, like the poor thing had personally offended him.

But what he couldn't ignore was this:

Haechan.

Two inches away.

Breathing.

Existing next to him with all that intense Haechan-ness.

The lab bench was small. Too small for two people, really. But after their class got rearranged because of some maintenance in the other wing, all lab partners had to share half the space they were used to.

Which meant Mark and Haechan were shoulder to shoulder. Hip to hip. Sharing a squeaky stool that groaned every time Mark shifted even a little.

"You're squirming," Haechan muttered, not looking up from the test tube he was carefully swirling.

"You're breathing down my neck," Mark shot back, failing spectacularly at keeping his voice steady. His knee accidentally brushed Haechan's. Again. "Also, I think this stool is haunted."

"That's just your chaotic energy vibrating through the furniture."

Mark glared at him. "You're not funny."

"I'm not trying to be."

Ugh.

It was infuriating. The smug look. The perfect posture. The steady hands that never once wobbled, even when dealing with fragile glassware and a burner flame. Meanwhile, Mark was trying not to knock over their shared burner with his thigh.

The problem was that the closer Haechan got, the more Mark started noticing things.

Like the faint scent of laundry detergent on his collar. Or the way Haechan's brow furrowed when he concentrated. Or how his fingers, despite all the handwashing, were still slightly ink-stained from notes he wrote too fast.

It was all... very distracting.

And Mark didn't want to be distracted by Haechan, of all people.

Haechan, meanwhile, seemed frustratingly unaffected.

"So," Haechan said casually, "you and Rhea from class—were you two ever a thing?"

Mark blinked. "What?"

"She keeps looking at you like you stole her charger or something."

Mark let out a confused laugh. "What kind of analogy is that?"

"A good one," Haechan said, not missing a beat. "Answer the question."

"We were partners for a week last semester," Mark said, drizzling their solution into the beaker a little too fast. "She didn't like how I organized my notes, said it made her itchy. Which, to be fair, is kind of how I feel when you organize notes."

Haechan looked vaguely offended. "Order is underrated."

"And you're overbearing."

"Flawed but efficient," Haechan replied, deadpan.

There was a moment where their eyes met, and it was like someone pressed pause on the entire room. Not in a dramatic, cinematic way. More like a static-charged, accidentally-brush-fingers-in-the-dark kind of way.

Too much. Too close.

Haechan looked away first, suddenly focused on labeling their sample like it was a timed test.

Mark exhaled like he'd been holding his breath since the start of class.

What even was that?

He needed air. Space. Maybe a therapist.

Instead, he cleared his throat and reached for their notes. His hand grazed Haechan's.

Again.

This time, Haechan didn't move.

Mark didn't either.

And for a second too long, neither of them acknowledged it.

It wasn't a moment.

But it was something.

Back in the hallway after class, Haechan caught up to him.

"Hey," he said.

Mark raised an eyebrow. "Yes, Lab Dictator?"

Haechan ignored the jab. "Tomorrow... if you want, we could go over the results again. Together."

Mark stared. "Like, outside of class?"

Haechan's ears turned a little pink. "Yes."

"Voluntarily?"

Haechan gave him a look that said, Don't push it, Tissue Guy.

Mark shrugged, trying to play it cool while his heart did some kind of gymnastics routine. "Sure. I mean, if you need me to help you understand something—"

"It's not for me. It's for the accuracy of the data."

"Right. Data," Mark said, trying—and failing—not to smile.

"See you, then?" Haechan added, already walking off.

Mark's stomach did a little cartwheel.

"Yeah," he called after him. "See you."

The thing about not being friends with someone, Mark realized later, as he stood at the third-floor study room door, was that you weren't exactly sure what to expect when they texted:

[Haechan]: Bring your lab notes. Meet me at the third-floor study room. 4PM.

It wasn't a command, either. Not exactly.

But here he was, at exactly 4:00 PM, with his notes and a bottle of soda he totally just happened to have. Not because he remembered Haechan liked the citrusy kind or anything. That would be weird. Totally. Just... a coincidence.

When Mark walked in, Haechan was already there, as expected. Sitting cross-legged against the wall, glasses slipping low on his nose, surrounded by highlighters, pens, and papers scattered like a well-organized war zone. And when Haechan looked up, their eyes met.

Mark's stomach did a flip-flop he wasn't prepared for.

Haechan smiled. Barely. Just a flicker. But it was real.

Mark froze. For a second, he forgot why he was even there.

"Hey," Haechan said, shifting slightly to make space on the floor. "You're exactly on time."

"I'm always on time," Mark replied, flopping down beside him with a dramatic thud. "You're just always early, which makes me look bad."

Haechan hummed. "I think you do that all by yourself."

"Rude," Mark snorted, reaching for his notes. He tried not to look at Haechan too much, but come on. The sleeves were pushed up. The smile was lazy. It was criminal.

Haechan handed him a color-coded sheet of paper without comment. Every detail of their lab data rewritten to perfection.

"You rewrote everything?" Mark squinted at it.

"It was messy."

"It was mine."

Haechan shrugged, eyes flicking to the side. "I like order."

"And I like breathing, but I don't rearrange the oxygen in people's lungs."

Haechan gave him a look. "That's the dumbest analogy I've ever heard."

"Thank you," Mark said proudly. "I specialize in dumb analogies."

They worked in silence after that. At least, at first. The kind of silence that settled in too easily. Comfortable in a way it probably shouldn't have been. Mark had to force himself to focus, even as Haechan's leg brushed his every time they reached for something.

Maybe it was the close quarters, but the way their hands kept touching as they passed pens back and forth was... getting to him.

Still, no weirdness. No overthinking.

Except his brain had already checked out. Because when he looked up, Haechan was staring at him, too close, too warm.

"You know," Haechan said, voice a little too soft, "you're not bad at this."

Mark blinked. "You sound surprised."

"I am," Haechan replied, amused.

"Wow. You're such a jerk."

But the way he said it was too soft, too fond.

Haechan didn't look away. His eyes stayed steady, not flirty but definitely not neutral. Something in them made Mark's stomach twist up.

"Only to people who get under my skin."

Oh.

That shouldn't have made his heart skip. But it did. And suddenly the room felt smaller. Tighter. Like neither of them wanted to move.

Mark just said, "Oh."

Haechan looked away fast, too fast. "Cool."

"Cool," Mark echoed, swallowing around the weird lump in his throat.

They sat there in silence again. This one felt heavy, not in a bad way. Like it was saying too much for either of them to unpack.

And then, because the universe loves comedic timing, the door creaked open.

Rhea popped her head in like she was making an entrance on purpose. Her eyes flicked between the two of them.

"Oh. Sorry! Didn't mean to interrupt your... whatever this is."

Haechan replied immediately. "It's not anything."

Mark added, "Literally just studying."

Rhea raised an eyebrow. "Right. Well. Carry on." Then she disappeared, door clicking shut behind her.

The air in the room had shifted again. Mark could feel something fragile stretching thin.

"I should go," he said too quickly. "Dinner. At home. Where I live. With food."

Haechan stood too, just as fast. "Right. Yeah. Food is... important."

They stood there. Not moving. Not talking. Just existing in that same strange space.

Mark scratched the back of his neck. "I'll see you tomorrow?"

Haechan nodded. Softer this time. "7:15."

"Always," Mark said, and wow, it came out quiet. Almost too soft.

Haechan gave him a look. Brief. Unreadable. Then turned and headed for the door.

Mark stayed behind a few seconds longer, heart still going way too fast.

He didn't know what they were.

But something had shifted.

And that was terrifying in a way he didn't quite have words for yet.