"Like I said before, I think the metal cylinder is like a robot-like dumpster. The doctor explained, "Then for the garbage bin, we humans are real garbage." If the garbage appears on the white floor tiles, it will be unsightly. If it appears on a black floor tile, then it will be fine. Earlier, the man in black fell beside the metal cylinder, but the metal cylinder began to grab the person behind him first. Do you still remember this?"

I nodded.

"I remember the mechanical palm of the metal cylinder sliding around on the white floor tiles, looking like it was wiping glass. I was stunned, "Could it be that he's wiping the dust off the white tiles?"

"I guess that's about it. Moreover, the metal cylinder will catch the person behind the man in black, probably because he runs faster than the man in black. If you're a cleaning robot and you encounter garbage that is blown around on the ground by the wind or a garbage that doesn't move, which one do you think is more unsightly?"

I felt my cheeks twitching.

Although the doctor's explanation sounds rather nonsensical, it is very reasonable from a certain point of view. Everything is for "looks" reasons. Get rid of the obstructive air man, clean up the trash that runs faster, and clean the floor that is soiled by the air man. In this way, isn't it equivalent to saying that we air people are filthy things that cannot be seen directly?

For the first time, I saw the malice of this trial in person.

I turned to look behind me, and the air people stood a dozen meters away looking at us in a daze. I think there must be a lot of smart people among them, who may have deduced the rules here. But those smart people did not dare to act rashly, and did not dare to pin their lives on this seemingly joke-like black and white rule. If you don't gamble on luck, they also have plenty of ways to safely get through metal cylinders.

It's a pity that I don't have any brilliant minds, and I can do as hard as I can with knowledge. Desperately observing the doctor's movements, desperately trying, desperately trying to the end. This trial was not good for me from the beginning. I have no intelligence, and my physical strength is very poor, and if I don't have the courage, then I have nothing. The doctor looked at the air behind him and smiled bitterly, it seemed that it turned out that even if the doctor said it in advance, they would not believe it.

"I don't think I have told my story yet. "Everyone misunderstood me, though it didn't matter—I wasn't a doctor by profession, a doctor was just a code name I gave myself." ”

"Huh?"

I was taken aback.

"But you treated the glasses girl for her wounds!"

"I just have some medical knowledge. The doctor shrugged, "To be honest, it's also half-. As the saying goes, I am in a similar situation. If I had to talk about occupation, I would probably be a professional patient. When I was a child, my body was very weak, so I thought about death while not being reconciled. When I had nothing to do every day, I began to teach myself medical knowledge, and later I also gave emergency medical treatment to others. All in all, I'm not a doctor. ”

Doctors, no, doctors who are not doctors look indifferent.

"But I don't think it matters, it's not my medical license. I just entered their hearts as a 'doctor'. ”

"But...... Why are you telling me this?"

"I'm just trying to say that I'm actually a guy who's been taken care of all the time. "Growing up, I received a lot of care. I think I'm causing too much trouble for the people around me, and it's better for them to think I'm dying sooner. Now that I think about it, maybe it's my self-defeating mentality that has alienated everyone. After becoming an air man, I was taken care of by a lot of people, so much so that I felt that I had to do something for others. The day I started thinking like that, I went from being a patient to a doctor. ”

The doctor looked at me quietly and I understood what he meant. He who was originally a patient can be transformed into a doctor who leads others. Then people like me may be able to make a little useful contribution. I suddenly felt that Riko's previous thinking was wrong, if everyone was in a small circle, then what was the difference between it and those who abandoned us in reality? Every time after class, the girls in the class would gather in twos and threes, and even everyone's position was vaguely a special restriction. If any child does not show up for leave, the position of the crowd in the class will be spontaneously and subtly adjusted. It's as if something is invisibly wrapping and suppressing us. I don't want to be like that, and since I'm already an air person who is far away from society, I want to be a little more freewheeling.

I told the doctor about the last trial I had with my seniors. However, I didn't say anything about how Riko got into this trial, or the light spots behind her. All I can say is about me, and Riko's affairs should be left to her own decision. And I also vaguely feel that the light spots on Riko's body are quite tricky. The doctor listened to my words and fell into deep thought.

"All trials should have rules. "You mentioned that everyone was killing each other, and I don't think you have found the right way to get through." ”

The doctor's words were almost exactly the same as Riko's thoughts.

"But I have a little speculation about your final details. The doctor said to me, "At the end of the trial, you said that you and your seniors were the only two left. Your predecessor struggled with the Death Scythe, which had the ability to die, and then you hid in a puddle. You're holding your breath in a puddle, not knowing what's going on outside. Then your senior dies and you clear the level alone. ”

"Hmm. That's it. ”

"Is that puddle common?"

Strange, why did the doctor ask the same question as Riko again?

"I just wanted to make sure, I think this puddle might be the key to your clearance. "Have you ever wondered what this puddle is for?"

"Hide from yourself?" I tried to speculate, "or maybe it's for drinking water?"

"It's possible, but I think it's more of a trap. ”

"Traps, but I didn't encounter anything terrible in the water?"

"Because that's not a trap for you. The doctor gave an intriguing smile, "That's a trap for that 'Death Scythe.' ”

Traps against monsters?

The doctor seemed to see my suspicion and began to explain it to me.

"You said you were killing each other with your swords in the underground labyrinth, why did you kill each other?"

"Because ......," I thought back to the hellish scene, "that monster will only attack the nearest enemy, and if you don't want to die, you have to push the others down in front of the monster and divert the target." In order to survive a little longer, I cut off the hamstrings of my companion and watched him be killed by monsters from a distance......"

"Well, I'll make a bold guess. The monster only attacks the nearest enemy because she is observing you through some kind of perception similar to sight. ”

"Are you saying that he kills whoever he sees?"

I was a little stunned, didn't monsters kill whoever they saw? I don't know why doctors should be so solemn about such a natural thing. But the doctor seems to be thinking about it seriously.

This is the case, which precludes his observation methods beyond distance or spatial limitations. Let's say a thought flashes through your head — like you start to feel fear — and then the Scythe of Death suddenly appears behind you and slashes you. ”

"It's like Mary in the city, you keep getting calls from Mary, and every time you get Mary, she gets closer to you, and finally she appears directly behind you......"

"That's right. In this way, the Death Scythe is not the kind of monster that pursues pure horror and does not conform to common sense and logic. I think he's more of a hungry beast or a robot that's set up to attack. However, the way the Death Scythe senses are not necessarily 'seeing', and I think infrared sensing is also very likely, because you said that the underground cavern is very dark inside. ”

"Well, there are barely torches on the walls, but there's not a lot of visibility. ”

"Are there torches still in them...... the doctor frowned, "so the thermal imaging hypothesis is unlikely. ”

"Huh, why?"

"I started to think that the water in the puddle might be able to mask your breath and temperature. "If the Death Scythe relies on infrared sensing to detect you, you can deceive his perception to a certain extent by hiding in the water." When the 'Scythe of Death' thinks he's killed everyone, then the trial is over. This puddle trap is designed to give the 'Reaper's Scythe the illusion that 'mission has been accomplished'. ”

"I see. But why do you say it's unlikely?"

"The reason is simple. The doctor shrugged, "Because you mentioned that there are a lot of torches stuck in the walls." With the interference of these heat sources, the Death Scythe may not be as quick to perceive as it seems. I don't think the God who gave us trials would be so merciful and weaken the perception of the Grim Reaper's scythe. So I'm still more inclined to the Grim Reaper, and the scythe also has vision. ”

"If I hide in the water, it should be able to see it. I thought for a moment and said, "The water in that puddle looks clear. ”

"And how clear is it?" asked the doctor, "can you see the bottom of the water?"

"The light was dim, but the bottom of the pit was still faintly visible. ”

"Can you see your own reflection?"

"Reflection......" I thought about it for a moment, "I think it should be, but I don't remember it very clearly." But what's the use of proving that the water is clear and you can even see the reflection?"

The doctor said solemnly.

"The water is clear, which means that the Death Scythe can see you in the water. Seeing the reflection means that the Death Scythe can also see itself. I guess this Reaper Scythe doesn't have any weird abilities like piercing walls or space jumping. ”

"I don't remember it ever doing that. I shook my head, "If he could have made it through the wall, we'd be dead." ”

"I think so, that means he'll get closer to you when he sees you underwater. The doctor continued, "Then he will slowly walk to the water's edge. He'll see a guy in a robe with a scythe standing between himself and you......"

"Do you mean?!"

"That's right, I don't think the Death Scythe doesn't recognize it as its own reflection at all. Just like many animals look in the mirror, they think that they are other individuals in the mirror. So the Death Scythe began to attack its own reflection. As you mentioned earlier, the Death Scythe prioritizes those who are closer to you. So he will abandon you and start attacking the reflection in the water. ”

"But...... Even attacking the reflection in the water is just a splash......"

"That's right, for the Reaper's Scythe, attacking the shadows in the water is just a useless exercise. "But I think the shadow in the water can actually attack the Death Scythe." ”

"What?"

"It's just a conjecture of mine. The doctor shrugged, "Your previous conjecture was that the trial would end when there was only one trialist, and I had my own speculation. I think the key lies in the 'instant death' of the scythe. What exactly is the so-called instant death? I think it can be a kind of conceptual death, which does not require physical intervention, and is more inclined to spiritual behavior. According to you, the Death Scythe is limited by its vision, and it is necessary to walk out of a continuous path in order to move, so I think the Death Scythe may not be as powerful as the Scythe in his hand. That's why I think having an instant scythe can kill the Death Scythe itself. ”

"Kill yourself?"

"That's right. By the time the Grim Reaper's Scythe decided that he was the target in the reflection, he might have died. Or the Reflection Scythe also has some kind of instant death, and when the actual scythe cuts into the water, both sides are killed by the other at the same time. I thought about it for a long time, and I thought it was more reasonable to say that the monster was self-destructive. There is only one monster in the entire trial, and it is logical that the monster dies to mean the end of the trial. ”

Will monsters be killed by their own shadows? This kind of reality seems impossible at first glance, but I believe it a little. There are so many supernatural things in this trial that I have absolutely forgotten the common sense I have built up over twenty years. If we had thought of the principle of reflection on the surface of the water earlier, and lured the "Death Scythe" to destroy itself, perhaps we would not have died so many people.