After the back wall of the cupboard was fully opened, Chioujen found that behind the cupboard was another cupboard. The cupboard behind the cupboard was similar to a closet. So, Chioujen stood in front of a small room that seemed to function as a closet. If there was no cupboard in front of the closet, then the room would be just a niche in the wall. Chioujen, who had been convinced that there was a secret passage behind the cupboard, was a little disappointed. He lay in the closet feeling a little tired after a while of fiddling with the lever to open it.

The more he thought, the more confused he became. He thought about the reason why people made a closet like that if it would only be covered by a cupboard. And, it was also not easy to open it. All of that seemed unreasonable. The existence of another way out behind the closet was a much more plausible thing. But, unlike the cupboard wall in front of the niche, the wall behind was a solid wall. Chioujen lay crosswise. The width of the closet was about one and a half meters. He had to bend his legs so he could lie in the closet. Because he had struggled to get to that place, Chioujen was reluctant to return to the subway station straight away. He decided to rest while lying down for a while.

He idly kicked the surface of the wall at his feet. Unlike the closet's back wall, Choujin felt something different from the wall on the left. There were certain parts of the wall that he felt were not solid. Chioujen stopped kicking. He got up to start checking at once. Chioujen discovered that some parts of the walls were not made of concrete. With her fingers, Chioujen felt more thoroughly on the surface of that part of the wall. Unlike the wall of the cupboard in front of him, which was made of wood, the part that Chioujen found was made of some kind of metal. Chioujen didn't know what kind of metal it was because when he touched the wall, he didn't feel like he was touching iron, But Chioujen was sure that the part wasn't made of wood. The problem was that the passage was so small that he doubted it was the entrance to a secret passage.

When Chioujen looked more closely using the flashlight, he realized that this passage was indeed similar to an entrance. But not an entrance for humans, more like a dog or cat entrance. In Chioujen's hometown, this kind of entrance was called the Dog Door. So-called because it was the entrance for dogs. For cats, this kind of entrance was called the Cat Door. The difference was in terms of size. The Dog Door was much bigger than the Cat Door.

Chioujen thought for a moment. A fairly large dog could indeed pass the entrance. A child would definitely be able to break through. But an adult, like himself, Chioujen, was a bit hesitant. If he forced himself, he was afraid he would get stuck in the door. No one knew he was there. Chioujen realized he was facing a pretty enormous risk. But he had to make a quick decision.

If I got stuck and couldn't get out, wouldn't I suffer for several days before finally dying of hunger and thirst?

Chioujen laughed to himself at the thought of that. It's ironic, so many things he had experienced and yet he must die stuck in a Dog Door.

As he continued to stare at the passage, he kept thinking about how to open it. He looked for something that resembled a lever, but he couldn't find it. It occurred to him to look for objects made of metal to break down the surface of the Dog Door. But he was still patient. Using such violence was a last resort. Chioujen then used his flashlight to illuminate the entire corner of the closet once again.

Then he turned around. He also highlighted where he had come from earlier. He looked again at the two levers in the cupboard. Suddenly, Chioujen realized that there was a part he had not noticed, namely the back wall of the cupboard that he had moved to the side. He had already seen from the front when he opened the cupboard. But he didn't see the other side because he had already moved to the side when he found the closet.