"I want you to leave the room," Arima said plainly.
"Leave the room…?"
He nodded. Haise blinked, glancing at the door he had only just come through.
"That's all?"
"That's all."
Haise slowly turned back towards the door, still not quite sure what he was supposed to be doing. Was there something outside that he needed to grab for today's training? Or had Arima abruptly decided that he was too busy to meet with him?
No sooner had he turned around when he felt a great force knock him forward, making him completely lose his balance and sent him crashing to the floor. Arima had kicked him.
Haise's head whipped around to look back at his teacher, confusion and hurt in his eyes, but too surprised to voice a question. Arima's face was unchanged. "Get up, Haise."
Haise obliged, expecting an explanation as he dusted himself off, but none came.
"Good," Arima emptily praised. "Now, Leave the room."
Eyebrows still knit in confusion, Haise hesitated for a second before turning around again. And again it wasn't a moment after Arima was out of view before he felt a hand grab him by the hair and pull with such force that he was completely thrown backwards and wound up on the floor once again.
He stared up at his superior, and finally asked, "What?"
Saying nothing, Arima made a hand gesture indicating he wanted Haise to stand back up, and again he complied. As soon as he was back on his feet, Arima grabbed Haise by the shoulders none too gently and turned him to face the exit.
He gestured a few feet in front of them. "There's the door. Your only goal is to turn the handle and walk out. Mine is to keep you here. It's a simple exercise, but a useful one."
Haise nodded, understanding now, and began bracing himself for the start of the challenge.
"And Haise," Arima added. Haise stiffened as he felt a hand lightly place itself on his lower back. "You're not allowed to use your kagune."
"Of course," Haise promised.
A few hours later, Haise lay exhausted on the floor, no longer even trying to get back up. He could feel his bruises healing just as they were starting to form.
Contrary to the other's condition, Arima had hardly a hair out of place as he walked away from his pupil.
"That's enough for today, Haise. We'll try this again tomorrow. You can leave."
After the first few days of repeatedly being struck down by Arima en route to the exit, Haise decided to try a different tactic. Instead of trying to overpower his superior, he would try dodging past him and running straight to the door. Dodging was his strongest ability after all, and, as he was always telling the Quinckes, "When faced with an opponent you can't defeat, even if it costs you an arm and a leg, run away."
And to be a good leader, he had to practice what he preached, right?
This tactic didn't last long. Every time Haise successfully dodged one blow, he was struck by the next. Every time he ran one step past the other, he was always dragged two steps back. Arima was always just a bit faster, always seemed to be able to predict what Haise would do, exactly where he would move as he scrambled to the door.
Despite what he taught his kids at the Chateau, Haise learned that there are some opponents you just can't run from.
They didn't do this training every day; there were many days where one, the other, or both would be too busy, but it was often enough that Haise would grow slightly anxious whenever he was called to Arima's office. Even when he wasn't called there to spar at all, even if it was just for coffee, or to chat about books, he would notice the door on his way in and wonder when the next time his superior would let him walk through it would be.
Arima always referred to it a simple exercise, but the emotions it made Haise feel were not nearly so simple.
"Akira-san, have you ever sparred with Arima-san before?"
"Yeah, a few times." Akira nodded as she ate another mouthful of her lunch.
Haise's eyes grew bright. "Really? How did it go?"
Akira laughed dryly. "Well, sparring with Arima really only ends one way for anyone. I did alright though." She stirred her curry thoughtfully. "But it's not something I'd like to do often. Why? Is he pushing you too hard?"
"No! No, not at all. I was just curious."
Truthfully Haise was wondering that same question, but he didn't need his "mom" worrying about him.
Haise once thought about asking Hirako for advice on their mutual teacher's strenuous exercises, but immediately thought better of it.
Once, when driven past the point of frustration and exhaustion during a particularly long session, Haise used his kagune. He hadn't intended to, but the door was there. The door was right there, and he was so close, and a voice in the back of his mind said that once he stopped playing around and gave it all that he had, he could finally get past Arima, make his escape, and win this stupid game.
After that round, Haise learned to never try using his kagune against Arima again.
Nightmares were already an almost everyday occurrence. Images of construction sites, pliers, hospitals, flowers, and scratched wooden chairs leaked from the cracks in the locked doors of Haise's mind. He didn't know where those nightmares came from, but shortly after Arima started sparring with him in this way he began having a new nightmare.
It was always in Arima's office, or rather, what he always immediately accepted as Arima's office in his dream, even though he would always realize all of the differences from reality upon waking up. This version of investigator's office was much larger, with endless ceilings, sometimes no windows, sometimes stained glass, always the same furniture, but spread further apart, and it had black and white tiled flooring. He recognized the flooring from other nightmares.
Maybe it was the tiling of another room he couldn't get out of, in another life.
He faced the exit, but he could never reach it. Often in the dream he couldn't even move. Just stare at the door in dread as it seemed farther and farther away.
A figure always came up from behind, resting their chin on his shoulder, wrapping their arms around Haise, constricting his already immobile arms to his sides.
He couldn't turn his head, but he could always see the white strands of the person's hair mixing with the ends of his own.
Was it Arima? Or someone else?
It's the same. The outcome will always be the same. The voice whispered. You can try and leave, but a metal beam will fall from the ceiling. The drugs in the coffee will start to take effect. There will be a hostage tied to the altar. False promises of other peoples safety will tie you to a chair. Someone else will be waiting for you in the flower fields. Over and over and over and over and over and-
In the morning Haise would rub his eyes over his morning coffee. It was just a simple exercise; he shouldn't take it so seriously.
"Leave the room."
Haise was curled up on the floor, again, exhausted and panting. He heard Arima's footsteps as they came close, and opened his eyes to stare at the other's shoes as he choked out, "I can't."
"You can't what?"
He looked up and met Arima's eyes, and gave a small shake of his head.
"I can't leave."
Arima knelt down next to his pupil.
"Then you've learned all you needed to from this lesson."
And he helped Haise up.