Even the score:

When a person decides to even the score, they try to get their revenge on someone who has cheated or done them harm.

Sungkyu, Woohyun and the ventilation way

The smel got worse and worse through time. 

"Hyung-ah, is it me or this smell is really similar?"

The two heard a 'crack' sound from somewhere: the sound of a piece of metal slid smoothly on a surface and made a loud clang when hitting something.

"What is it?"

The damn smell got even stronger after that noise.

"Should we get back to see what's happening?"

"I don't think so! Please don't hyung-ah!" 

Covering his ears, Sungkyu was so stubborn to hear and just turned around.

"Hyung-ah!"

(Sungkyu's POV)

This smell! They gave me a load of memories. Why are they coming now? I tried to forget it for a long time but I just can't help. 

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A/N: Sungkyu's speeches are in purple.

[Flashback 1]

Soryong turned open his locker and stepped right back as he saw a jar of clear liquid with a disgusting light yellow color.

"What is this?"

There was a piece of note in the jar, written "If you kept being stubborn, your life will end up like this!". Obviously, the note was deccomposing in the liquid. Soryong took a sniff of it.

"Chlorine bleach! How did..."

He looked around the corridor. The note was not wholly decayed, so it hadn't appeared more than 15 minutes ago.

"Must be somebody in the Chemistry club. It's not easy to get chlorine."

[Flashback 2]

In the previous year Science festival, an accident occurred. Thirty students, 2 teachers and over 90 visitors were taken to the local hospital. There were 3 reasons to lead to this miserable injury:

- An unproffesional experiment of dry ice bomb.

- Lack of care in some performances that release acidic gas.

- A show of chlorine bomb and water rocket was cancelled due to unexpected reaction led to an explosion.

After that, the director of the festival was seriously fined and the Chemistry club disbanded until the assemble in the next schoolyear.

Woohyun had to breathe in the stink. Inhalation now became too difficult for him. His eyes started to sore and tearful. The pungent gas stuffed his nose. Woohyun tried to keep his body low and finished his journey. "Just a bit more, just a short distance and I'm into the Chemistry room!" Crawling now was not an easy task anymore when breathing was already arduous. "Sungkyu hyung, I'm really near to the light now!" 

The weak neon light in the room attract his eyes since tear duplicated it into several different colors. Woohyun dried his eys but each times he did that, his eyes got hurter and tears just fell more and more. His brain was paralyzed. He couldn't think of anything than keep up his progress to the room, the only place to save him. The arms weren't controllable and went weaker after every inch he went.

Finally, he touched the blind that separated the way and the room. He tried pushing it aside to jump down but... it was hard sealed several hours before and the wax had harden since long ago. Woohyun hardly had any energy left as the gas poisoned his lungs and now breathing became impossible for him. The only thing that could move now was his right eye. It turned weakly in tears and sent his brain the last image: a small hole in the chlorine cyclinder.

Sungkyu suffered the same condition as Woohyun. His senses were useless now. The terrible chlorine smell gave him a vomit. "I wish I didn't play that thing to him. Now the one who pays it is me!" Sungkyu struggled to reach the entrance and raise his flashlight.  His eyes were wide open like a year ago that he saw the way was closed (by somebody). The last thing he could do was close his eyes. The flashlight fell off his hand.

Next: Hoya. What would happen to him? What was with the pills he took?