Something I haven't explicitly cleared up but I definitely should:
MC is not in a relationship with anyone at this point. Imagine it like a platonic deep route (so far!). Also, Saeran has been going through therapy after a period of time in the hospital and has now made a delicate peace with Saeyoung. :) Thanks for reading!

Saeran has entered the chatroom

MC:

Saeran! How are you?

Saeran:

Fine, I guess.

Yoosung:

Hey! How's Seven?

Saeran:

Yoosung:

Jeez, why are you so weird?

MC:

Maybe Saeran's having a bad day. But that's what we're here for!

Saeran:

I'm fine. Honestly. Really.

New Message Received

From: Saeran

I'm not.

MC:

MC:

I have to go. I have a big test tomorrow!

Yoosung:

Good luck, MC!

MChas left the chatroom

Saeran has left the chatroom

Yoosung:

Yoosung:

Honestly, Saeran's only on here when MC is. Rude.

Yoosung:

And what's with the long pauses?

Yoosung*has left the chatroom

(In the text messages)

Saeran:

I'm not.

MC:

What happened? Are you alright?

Saeran:

I just said I'm not.

MC:

I mean health-wise.

Saeran:

Oh.

MC:

Well, come on, talk to me.

MC:

Saeran.

Saeran:

Fine. Saeyoung was being a dick.

MC:

I'm sure he didn't mean to hurt your feelings. What happened?

Saeran:

Nothing, he just got on my nerves.

New Message Received

From: 707

I think Sae…

MC:

Hey, gimme a sec. I'm getting a text from Seven. Maybe we can clear this up together?

Saeran:

Wait

Saeran:

Don't go

Saeran:

Don't talk to him

Saeran:

He only lies.

MC:

What? Something big must have happened.

Saeran:

Yeah. He made fun of me for having a crush.

MC:

Well, that's rude. But he did guess correctly, right?

Saeran:

Maybe.

Saeran:

But that's not my point. He made fun of me for it, and I almost screamed at him.

New Message Received

From: 707

Is that go…

MC:

Another text from Seven.

MC:

I'll go give him a piece of my mind!

Saeran:

I said wait!

MC:

Okay…? I just want you guys to get along…

MC:

Promise me you'll try to talk to him when you calm down, at least.

Saeran:

I promise.

MC:

I'm really happy you're adjusting well! Fighting is perfectly normal. After you two make up, your relationship will be even stronger.

Saeran:

I hope so. If you want me to, I can go talk to him now.

MC:

okay! I'll wait for you here.

Saeran turned off his phone and sighed deeply. Not a single part of him wanted to go to the other room, or even talk to Saeyoung. But MC thought it was a good idea, and it was rare for one of her ideas to turn out badly. So, Saeran peeled himself off his door and walked to Saeyoung's room.

"Saeyoung…?" he tapped on the door

"Yesss?" Saeyoung sang.

"Remember how my therapist told me I needed to express positive feelings more?"

"Um… Nope." This is now how I saw this going. Fake it til you make it, thought Saeran.

"Well, he did, and I wanted to tell you that… I'm sorry. For snapping at you." Something in Saeyoung's eyes changed, softening him to the real Saeyoung.

"It's fine. A sensitive subject. I get it. But seriously, do you…?" A hint of 707 returned near the end of his statement. Saeyoung's face pulled into a smirk as he regarded Saeran, waiting for an answer. Saeran dutifully rolled his eyes.

"Do I what?" Saeran asked, mentally bracing himself. From knowing the new 707 for a few months, Saeran knew the look sprouting in his face.

"Do you like like MC?" Saeyoung smirked. His glasses shone with the light emanating from the monitor behind him. In his mind, Saeran was panicking. Lying was bad, very, very bad, but, at the same time, Saeyoung wasn't known for his secret-keeping abilities.

"I…I…Fine. Yes, I like MC." He replied, looking directly at Saeyoung, who fist pumped the air and whooped before spinning around in his leather office chair. Perhaps it was just the bad lighting in the room, but Saeran could swear he saw Saeyoung's face fall for a split second. At the moment, though, Saeran thought nothing of it.

"I knew you were lying when you said you knew her crush!"

"So, can you promise me you'll let me have her?" Saeran hazarded. Saeyoung looked up, a masked 707 smile plastered over his face.

"Hell yeah!" He burst out giggling, "You two would be awesome together!"

"Well, then," Saeran rolled his eyes and asked, "Could you do me a favor and delete the texts you sent MC about me?"

"All of them?"

"No, no, just the ones you sent fifteen minutes ago."

"Oh, yeah, duh!" Saeyoung opened his phone and started to unsend the messages, carefully waiting for Saeran to stop watching and walk back to his room to tell MC they had made up. As Saeran's socked feet padded down the hall, Saeyoung looked at the messages. How had Saeran known those had existed? He had only sent those to MC. So he had talked to MC about their fight. Given the timeframe, Saeyoung could conclude that MC was the one who had convinced Saeran to apologize. That meant she was lowkey mad at Seven, which meant she was purposefully avoiding his texts. Saeyoung's finger hovered over the unsend button, until he finally tapped it to unsend his two messages. Instead, he began to write a new message. Saeran was his brother, which meant Saeyoung knew him better than anyone. So, Saeyoung knew Saeran would never gather the courage to tell MC. And Saeyoung knew that he wasn't going to give up MC that easily.