The fourth floor of the school opened up to the surviving students. They quickly explored it together, mostly finding ordinary classrooms and laboratories. Makoto managed to stumble on another picture, this time of Sayaka, Celeste, and Hifumi, and as Celeste confirmed she had no memory of the event depicted, this simply provided more evidence for the idea that they had lost their memories - as though they needed more. They also found a lab filled with chemicals, including vitamins and proteins that excited Sakura, but more importantly, containing several poisons. Kyoko immediately ordered the poisons flushed down the toilet before anyone could have the chance to use them, and Byakuya was the only one who expressed any resistance to that idea - likely out of resentment for Kyoko giving orders rather than any nefarious intentions, Kyoko reflected - so her order was quickly followed.
The most interesting thing they discovered, in Kyoko's estimation, was two locked doors: one to a data center, and one to the headmaster's office. Both seemed like they could hold important clues, but while students discussed how to get inside, Monokuma showed up and all but told them that the mastermind themself was hiding in the headmaster's office. Then he added a new rule to the handbook: no breaking down locked doors. Kyoko thought about picking the locks instead, but after careful investigation she concluded that the locks were a magnetic sort that she did not have the tools to pick. Kyoko also suspected that if they tried some other way of forcing the door open, such as explosives (should they be able to use the chem lab to make any), the bear would see the distinction between blowing up the door and breaking down the door as merely semantic, and punish them anyway.
So, she had no choice but to ignore that tantalizing mystery for the time being. It seemed likely that the only way to get into those rooms would be if someone sacrificed themselves to break the rules, or perhaps if the Mastermind got bored enough to open it themselves. She thought about assigning guards to keep watch over it, just in case the Mastermind did open the door, but that seemed a lot to ask of just seven students, especially if she wanted them to guard in pairs instead of being left alone at night, and all for a door that may never open.
After finishing investigating the fourth floor to her satisfaction, Kyoko was disappointed but not surprised to find that the group was just as imprisoned as before, and no wiser to their situation. There was only unexplored floor left in the school, if the map she had found at the start of all this was accurate, and it was clear by now that they could not access it unless another murder ocurred.
During her investigations, she kept an eye out for Ethernet cables and ports. She found no cables, but she did find a couple ports in classrooms. However, they were in full view of security cameras.
She and Celeste decided to recheck all the old rooms too, looking in every nook and cranny, even underneath and behind couches (they got Sakura's help when needed), hoping to find a misplaced cable or hidden port. It took the better part of a day before Kyoko realized there was one room that she had skipped over in her earlier investigations: the second floor boy's bathroom. That floor had opened while she was partnering with Byakuya, and he had been the one to check it out, assuring her that there was nothing out of the ordinary. She had accepted that, as the woman's bathroom certainly held no secrets, and she did not want to deal with convincing Byakuya or anyone else that it was perfectly acceptable to let a woman into the men's room during a death game, and rooms like the library had seemed far more promising anyway. Now, though, she wondered if that had been a mistake. She could not expect Byakuya to be as thorough as her.
Sure enough, when Kyoko investigated the boy's bathroom while Celeste stood guard outside, she found an odd seam in the back wall of the storage closet, one that was not there in the storage closet of the nearby woman's bathroom. A little more investigation, and she found a way to push open a secret door into a hidden room.
Why the school had a hidden room accessible through the boy's bathroom, Kyoko had no idea. It seemed unlikely the Mastermind had built it themselves in the time since the Tragedy. Especially since, as she looked around, she saw mainly volumes upon volumes of old yearbooks stacked in dusty bookshelves. Actually, the whole room was thickly covered with dust, including the big desk at the center of it, which meant, Kyoko realized with growing excitement, that the Mastermind probably did not know this room existed, or else they probably would have cleared it out before the killing game began.
Kyoko knew she could not investigate the boy's bathroom for long without attracting the mastermind's notice. So, she quickly rifled through the desk, and made several important discoveries. The first was a handwritten note that read "You must not leave" tucked into a student registry. Kyoko figured this was an oblique reference to the Tragedy, though she wondered why it wasn't written "We must not leave." Perhaps it had been written by a school leader, such as its actual headmaster, who wrote it to the students before leaving himself? In any case, it was the least important of the clues.
The second clue she found was within the contents of the registry itself. She didn't have time to peruse every name, but she quickly skimmed it, looking for a name she recognized. She found the names of every one of the fifteen students that had begun this killing game, including herself, all listed as members of the same class. And also listed as a member of that same class was a sixteenth student whose name Kyoko did not recognize: Mukuro Ikusaba. There were no other details listed, not even ultimate talents, so she had no idea what Mukoro's talent was, nor could the registry inform her of her own. Kyoko had no idea if Mukuro was someone who had died before the killing game began, the Mastermind behind everything, or something entirely different. But it was a lead, at least.
And the third and last notable discovery was the very thing she had been searching for: an ethernet cable. It was tucked into one of the desk drawers. As Kyoko looked around, she also spotted an ethernet port embedded in one of the walls.
Kyoko took just a moment to contemplate that. That must have been intentionally wired into this secret room, so she figured the room must have been used by a male school administrator, probably the headmaster, so he could work on some secret project, sending emails he did not want to risk anyone else intercepting. That probably meant this particular network connection would only connect to certain school systems, not the internet, so as to prevent cyberattacks. If true, that'd be disappointing, but likely still worth it. And Kyoko had spent enough time fruitlessly investigating other rooms, she hoped the Mastermind wouldn't notice if she spent just a little more time in the bathroom. She considered leaving and coming back later instead, but thought it too risky, as the Mastermind may learn of the room and prevent access to it. So, her mind made up, she strode back out of the secret room and out of the boy's bathroom.
"Anything?" Celeste inquired as Kyoko joined her.
"No," Kyoko shook her head, feigning disappointment. "But, um…" she scrambled to think of a good lie, careful not to look at the surveillance camera trained on them. "I could use your help with… something."
"Why, Kyoko!" Celeste said, feigning offense with a big smile plastered across her face. "In the boy's bathroom? How scandalous! Truly, your perversion knows no bounds." She tittered. "Okay. I don't think anyone will disturb us. Let's have some fun, girlfriend." Celeste sauntered into the bathroom, pulling a blushing Kyoko after her.
Once they were safely away from the camera, Celeste's flirtatious demeanor evaporated. "What did you find?" she asked seriously.
"I… um…" Kyoko said, flustered. She took a moment to compose herself. "That was quick thinking," she finally said.
Celeste nodded.
"Over here," Kyoko said, leading Celeste into the secret room.
"Interesting," said Celeste, as she looked around. "Lots of books. You need my help to read through them quickly?"
"No," Kyoko shook her head. "They're old yearbooks, while it's possible they hold clues, they're most likely too old to be relevant. But I did find this." She held up the ethernet cable, then pointed at the socket.
"Excellent," said Celeste, smiling lightly. "One second." She reached down and carefully pulled the laptop out from under her skirt. "Hey Alter Ego. Guess what we found?" she said as she placed the laptop on the desk. Kyoko quickly moved to plug it into the network.
Alter Ego appeared on the screen and paused as he took in his new surroundings. "A secret room? This isn't on any of the maps - oh!" Alter Ego cried out in surprise as Kyoko finished plugging him in. "That feels funny. Yes, I see now. Good job! I'm in the school's network! Hmm… there's no obvious way to contact the outside world. But maybe… Well, I'll see what I can find! I just need some time. I won't let you down!"
Kyoko nodded. "Just be careful, alright? Don't tip off the Mastermind to your presence."
"Right!" Alter Ego confirmed. "Just leave it to me!"
"It'll have to be a boy who meets with you next, to avoid suspicion," Celeste commented. "Probably Makoto. We may send him to check on you tomorrow."
"Okay!" Alter Ego said absently, clearly distracted by the flood of new data to analyze.
Kyoko glanced around the room one last time to see if there was anything she missed, then walked out, followed by Celeste.
Kyoko walked quietly towards the bathroom entrance, before Celeste stopped her. "One second," she said, before reaching up and ruffling Kyoko's hair a bit. Kyoko stared in confusion at the unexpected touch, until Celeste turned to the bathroom mirror and smudged her own lipstick. "There. Gotta sell it, girlfriend," she said mischievously.
Kyoko managed to hold back the blush this time, and nodded. "Thanks."
"Don't mention it," said Celeste, already walking towards the exit. "Come on."
Kyoko followed her out, smiling, though for a different reason than she hoped the Mastermind suspected. With Alter Ego in the network, they may escape the bear's game yet.
…
That evening, a couple hours later, Monokuma called them all to the gym once again. "Ahem," the bear began shortly after the seven surviving students arrived, appearing out of nowhere on the gym's stage as usual. "Let's get this show on the road!"
"Another motive?" Hiro groaned. "So soon?"
"It doesn't matter!" Hina proclaimed. "Those of us that remain would never turn on each other!"
The bear clasped his paws to his face. "Is that so? Well, I've decided I've been too easy on you all, giving you days between trials and motives. This particular motive, I think it should stick with you for a bit, simmering under the surface until it finally boils up into a fountain of despair! Puhuhu!"
"Quit your inane prattling and get to the point," Byakuya ordered.
Monokuma smiled darkly. "Guess what? One of you students has been working for me all along. One of you students is a spy, a traitor, an accomplice! This whole time, they were under orders to report your activities to me and to kill one of you if too much time passes without any murders! Luckily, you all are so bloodthirsty, even with all of your speeches and swears and suspicions, my spy has never needed to step in! Puhuhu!"
Kyoko's mind reeled at the implications. It was a possibility she had considered before, of course, but had dismissed: none of the other students seemed capable of betraying them. Makoto and Hina were so… innocent, in a way Kyoko did not think could be faked. Byakuya was too egotistical to serve someone. Hiro was too dumb. Sakura was too honorable. Celeste… a shudder passed through Kyoko… observing Celeste for signs of not being what she seemed had been part of the motivation for pairing up with her in the first place. Kyoko had never found anything suspicious and had now come to trust Celeste, but she had to admit, she now knew that Celeste had the skills to hide such a betrayal from her, even while under constant observation. Plus, Celeste had confessed to wanting to kill… Oh no. Could it really be her? Or was the bear just lying? She would much rather believe he was lying. But it seemed like the bear had not lied yet...
A voice cut through the silence. "As I suspected all along," Byakuya scoffed, showing no signs of wrestling with worries of his own. Kyoko had to fight the urge to roll her eyes, but noticed Celeste had given in.
"Hang on, if that's true, why would you tell us that?" Makoto demanded.
"I no longer need their help," Monokuma shrugged. "You are now few in number. At this point, suspecting one another will do more to move the game further."
"Why would we believe you at all?" Hina asked, her hands balled up into fists.
"Hey yeah, you could be lying!" Hiro declared as though the idea had just occurred to him - which it probably had.
"Believe me or not, it's the truth!" Monokuma roared loudly. Then he smiled and calmly said, "And either way, the possibility that your friend is a traitor, well, that will lodge itself in the back of your mind like chewing gum under your shoe. You'll never be able to get rid of it completely, right? How will you ever trust one another again? Puhuhu! Have fun!" With that, the bear scurried off and disappeared.
Silence reigned as everyone gathered their thoughts.
Surprisingly, the first to speak was Sakura. "There is something I should tell you all," she announced softly.