Players, Please Board the Train-Chapter 86: Mutant Attack

"Puzzle Solvers who answer incorrectly will be punished."
The Doll's voice suddenly sharpened. The two people standing behind the door changed expressions at the same time and bolted for the windowsill!
Almost the instant they jumped down from the second floor, the office door was smashed open, and a shadow immediately fell over the two backs!
At that critical moment, Lin Pei performed a difficult twist to catch the underside of the windowsill, and Xu Huo—exposed midair, still holding the piano wire—became the mutant's first target!
Time was tight. Xu Huo didn't even have time to swing his sword. He had only managed to bring out the Ox Shield when the pale, frog-limbed shadow slammed into him and rolled across the street into a clothing shop!
The mutant pressed itself flat against the shield, clutching the shield's rim with both hands, its huge mouth snapping downward and biting wildly. While dodging, Xu Huo got a good look at it—its face vaguely human, but its eyes seemed degenerated, eyelids fused shut, and its teeth and tongue dripping with mucus!
A spray hit Xu Huo in the face. He used his knee to flip the shield over and, taking advantage of the gap as the mutant flew past above his head, dashed out of the clothing store toward the track in the middle of the street!
He covered a fair distance and inevitably stepped on a Doll on the ground. The shriek sounded and the mutant burst through the window, chasing the noise!
From the Doll's sound to the mutant's leap, not even a second passed, but their speed difference was huge. Just as Xu Huo's foot moved off the Doll, the mutant had already lunged in front of him. He managed to raise the shield and block, but both he and the shield were violently hurled into a tree beside the office building!
He bent down to avoid the mutant's swinging arm, but those human-like nails easily gouged into the tree trunk, carving several grooves... Xu Huo immediately realized that in both speed and strength he was no match for the mutant!
While bending, he snatched up the Doll at his feet and flung it far away!
"Waaaah!!!"
"Waaaah!!!"
The sharp screams rang out more than ten meters away. The blind mutant quickly turned toward the noise. It hadn't run far before being drawn again by the sound of a Doll it stepped on, and it started tearing and chewing wildly on the spot!
On the hard ground it raked grooves with its bare nails. Most of the surrounding Dolls were torn apart and swallowed alive, but soon its emaciated chest and abdomen, ribs and hollowed stomach protruding, vomited them all back out.
After vomiting, it crouched like an animal, its thin long arms on the ground, ears raised as if listening to something.
The town fell silent again. Guided by the piano wire, Xu Huo landed silently on the roof of the office building. He watched the person who had the same outward appearance as him but had been completely reduced to a beast, uncertain how this would end. Somewhere in the town, a time-telling voice suddenly rang out:
"It's twelve fifteen! It's twelve fifteen! The night is so beautiful tonight, the moon looks lovely too. People who know better should be lying in bed sleeping now."
At the sound, the mutant immediately ran toward it. On the way it stepped on several Dolls; after picking one up it seemed to realize it wasn't edible and tossed it aside, then climbed the wall and leapt across rooftops toward the little house where the sound came from. Soon after entering, the alarm clock that was announcing the time stopped.
Xu Huo waited a while but the mutant didn't come back out, so he moved through the air and approached that single-family house.
He circled the exterior once and couldn't find the mutant, so he went inside.
The lighter's flame was enough to illuminate the small room. Following damp footprints on the floor, he walked to the fireplace, hesitated for a moment, then stuck his head in and looked up into the dark chimney.
The chimney opened directly outside and faint daylight could be seen. Beneath it stretched a narrow passage disappearing out of sight, the walls all etched with claw marks.
Xu Huo noticed the passage below the chimney differed from the chimney itself; it was made of metal. At regular intervals on both sides were rows of round holes arranged like a grille.
He stepped back from the fireplace and checked the rest of the house. He noticed a lock of hair peeking out from the edge of the ash. When he dug it out, he pulled out a half-faced human head.
He kept searching. Layer upon layer, he found at least five or six heads. Some had rotted to bone, others seemed to have died only a few days ago.
He filmed the heads for evidence, then put them back in the ashes before leaving the small house.
Just as he walked out, Lin Pei—who had escaped the mutant the moment it appeared—came out from a nearby shop. "You're really lucky to have gotten away."
Xu Huo raised his lighter and stared at him.
Lin Pei looked guilty. He said, "It's not that I wanted to abandon you, but in that situation, I... "
"That's fine." Xu Huo cut him off lightly. "If it were me, I'd drop you and run too."
Unsure whether he was being held grudges against, Lin Pei hesitated and then changed the subject, "I saw light over here so I came to check. What were you looking for in there?"
Xu Huo walked back along the track. "The mutant was lured to that house by the alarm. That house is a holding place for mutants; the exit has a grille."
"During the daily puzzle time, the exit grille should automatically close, so mutants can't get out, making puzzle times relatively safe for players."
Lin Pei hadn't expected him to have discovered such an important detail. "But not every puzzle place is safe. We just got tricked a moment ago."
"Places where children often appear tend to be less dangerous." Xu Huo paused, then asked: "Do you know how many mutants are in this town?"
"Probably more than three." Lin Pei said. "They don't seem to appear all at once."
"Although it's called a town, the area is large and the mutants could be scattered in different spots, so each time a sound just over 60 decibels occurs, it might only attract one."
"But above 80 decibels it's hard to say."
The game background specifically mentioned 60 and 80 decibels. Loud talking, puzzles, alarm clocks, bells, and Dolls are all under 80 decibels and can attract mutants. Whether very loud noise would draw every mutant is unknown, and players dare not test it.
Xu Huo stopped walking. When he had been thrown by the mutant earlier, the noise should have exceeded 80 decibels. Though the sound vanished in an instant, it did not draw a second mutant. Lin Pei's suggestion about distance was one possible explanation.
Tonight's mutant and the one that ripped up a car near the east gate were clearly different species. With two types of mutants and unknown numbers, killing or confining them would be very difficult—unless the original holding places had only one entrance and exit, in which case they could simply block the exit.
But there were large woods beyond the town, so the mutant that attacked at the east gate might not be staying inside the town. Could the trap cages that once held that mutant still contain it?