It wasn't difficult to find a Challenge Door to take on. That was because, different from the safes, the challenge doors were clearly marked on the map. There were fifteen of them.

Tenko choose to go to the closest Challenge Door, which happened to be number 9, and was only one floor below the Ultimate Entomologist's Lab, being on the second floor of the classroom building.

The two quickly got there, and found a locked door that had some sort of scanner installed right next to the handle. Tenko took the initiative to hold up her Monopad to the scanner, and what she saw caused her blood to freeze.

It was pretty similar to the message from the safe, it said:

"Challenge Door #9. Type: Puzzle. Reward for Completion: Part 9 of the Adamantis Puzzle and 10000 Monopoints. Time Allowed: Five Minutes. Players Allowed: 1. Punishment for Failure: Loss of Hand. Open?"

Tenko took a deep breath and forced herself to be calm and analyze the situation for any possible clues.

First, she saw that the challenge type was still puzzle, and remembering Kirumi's hint, she theorized that it was probably due to the fact that both of their safes and the challenge door were in the same place: The classroom building.

Second, the prize was "Part 9" of something called "Adamantis Puzzle" (aside from the Monopoints). It was reasonable to assume that the prizes of the other doors would also contain pieces of that puzzle. And thinking about her own hint, Tenko assumed that this puzzle would be something very important for the game, perhaps even relating to the team objective.

Third, there was a new part called "players allowed". This door only allowed a single player to enter, but that also meant some of the other doors could be completed in a team. Tenko had a few ideas about how such a mechanic would work, but she would need more data to make any reliable theories about it.

Finally, she could not ignore it anymore, and actually thought about the punishment part. She had been worried ever since she saw the words "Punishment for Failure: None" upon checking her first safe, but the rules of that door pretty much confirmed her fears.

The group that had captured the Ultimates and was forcing them to play that game seemed to be willing to allow them to be hurt in the process of playing. So it wasn't much of a stretch to think that they would be willing to allow them to die, as well. And continuing that line of thought, that meant there was a lower possibility that Monokuma's words about killing them being a bluff.

Tenko put a hand on her face and tried to organize her thoughts for a few seconds.

"Tenko?" Kirumi called, concerned.

Hearing that, Tenko managed to snap out of her tense state. She showed Kirumi the rules on her Monopad and saw the girl's face blanch.

"That... is concerning." Kirumi said "What do you want to do?"

"Well..." Tenko closed her eyes and thought, before pressing the screen to decline "I definitely don't want to get into anything like this without gathering as much information as possible first."

"Then..." She started "Could you take a look to see if it's the same thing for you?"

Kirumi nodded and held her Monopad to the scanner, then she looked at the screen.

"It's almost the same thing, except that instead of 10000 Monopoints, it's 5000 Monopoints and a 'Bug Beacon'." She said.

"A 'Bug Beacon', huh..." Tenko thought about it "I imagine that it would be something useful for your objectives in the game, but not necessarily for the other players."

Kirumi pressed the button 'NO', and then Tenko closed her eyes and thought seriously about what should be the next step.

"I think we should go around and try to get all the information we can from the safes and doors without actually activating them. Also, there could be other useful things that appeared in the school after the game started." She eventually said.

Kirumi agreed with the proposal, and they left.

And so, they went around the school, trying to get as much information as possible. And Tenko decided to organize their findings as a series of notes on her Monopad, which Kirumi also copied.

First was the fact that the challenges, both safes and doors, were indeed divided in a number of types, based on their location. "Puzzle" types were inside the school building, "Game" types were inside the casino, "Task" types were on the outside, "Challenge" types were on the underground and "Collection" types were inside the second building. There didn't seem to be any challenges inside the dormitory.

Second was the fact that some of the doors and safes had requirements in order to be opened. Most of them were in terms of Monopoints (including one particular safe whose requirement was fifty thousand Monopoints and whose reward was ?), but there were three safes whose requirements were possession of certain puzzle pieces (one, four and fifteen, to be exact), as well as two with unknown requirements (again, the ? thing) and five had requirements that seemed to be specific for each Ultimate (one example for Tenko was having the task information of a specific Ultimate, while one for Kirumi was having a bug beacon).

Third, there were a lot of other challenges that had punishments for failure, including every single one of the challenge doors. And regrettably, all the punishments for the challenge doors were things like losing arms and legs, losing eyes and that sort of scary threat. Challenge Door number 8, in particular, actually had "Death" as the punishment for failure, which really freaked out Tenko and Kirumi. The punishments for the safes were lighter in certain terms, with things like losing a particular number of Monopoints, being unable to activate any safes or doors for forty eight hours and the very ominous "release of restricted information". Some of those punishments were also unknown.

Fourth, there were four types of outcomes for the "Players Allowed" part: 1, 1-2, 1-3 and 2. There were five safes in total in which the players allowed were two and only two, and all of them were inside the casino. In there was also the single door that was the same way. Tenko theorized that those kinds of challenges were adversarial in nature.

Fifth, there didn't seem to be a pattern for the number of Challenge Doors in each "area". The outside area had just a single door, while the second building area had a whooping six of them. The other three areas were in between.

Sixth, the casino also contained an electronic shop, in which the players could buy and sell stuff using their Monopoints. It was even possible to sell the "hints" they had obtained. The things they could buy were divided in things that were specific to each one (in Tenko's case it seemed to be based around information, like revealing a lot of those "?" , while in Kirumi's case, there were bug beacons and other bug stuff, whose purpose wasn't clear, but apparently needed something called "golden bug" to be used, which was probably the "special bug" mentioned in Kirumi's Individual Objective) and things that either of them could buy, from simple stuff like a tracker that can tell you which safes were already owned, to a very concerning card, which you could use to force another student into a bet, as long as the terms of the bet were considered "fair" by Monokuma.

Seventh, and that was actually something that Kirumi noticed, instead of Tenko. There were apparently no bugs anywhere in the school that wasn't Kirumi's Lab. Bugs could pretty much get anywhere there were humans, so for there to be no bugs of any sort inside that place was concerning, specially given that it seemed to have been abandoned for a long time. It implied that the place was completely isolated from the outside world to an outright disturbing degree.

Still, they eventually made their way back to the place they started, standing right before Challenge Door 9.

"I guess this is it." Tenko said "I have to do it."

"Are you sure?" Kirumi asked "It's dangerous."

"If I'm right, taking those sorts of risks will be necessary if we want to complete the team objective, and thus survive." Tenko said, taking a deep breath to muster her courage "Hesitating at this point would just make things more difficult in the future."

"... I understand." Kirumi nodded, after a pause "But you will remain in contact via the Monopad, right?" She used a finger to touch the Monopad she was carrying, for emphasis.

Tenko smiled and touched her own Monopad, then she turned to the door, set her face into a determined expression, and pressed the Monopad against the sensor. And this time she pressed yes.

The door opened, and Tenko saw a few new words on the screen of the Monopad:

"Door Unlocked. Please proceed inside the room within the next ten seconds."

Tenko walked inside, and the door started to close. Tenko heard a final "Good luck" from the outside before it closed fully.

It was a small room, and most of the walls and ceiling were covered in posters depicting groups of people. The only place where that wasn't the case was a small bit in the center part of the north wall (the door was to the east) where a computer screen and keyboard were placed. In front of it was a small stool.

The Monopad beeped again, this time flashing with instructions that said to sit at the stool, and she soon noticed that it was bolted to the floor.

The Detective sat down, and she heard a sound coming from the ceiling. A hidden hatch in there opened and from it came two... tubes of some sort, metallic tubes whose purpose was definitely not positive. The two tubes stopped going down when their openings were at the height of Tenko's shoulders.

Again, words appeared on the Monopad. It was written "Choose what arm". And it was clear what she needed to do, so even though it was terrifying, Tenko slipped her left arm into the left tube.

After a moment, she felt her arm being trapped by some sort of manacle, and the second tube retreated back into the ceiling. The computer screen in front of her finally lit up, showing the words "Challenge Start".

Then a timer appeared. It started at 05:00, and began counting down.

Tenko just hoped she would be able to use her time the right way.