The train moved smoothly.
Like nothing was wrong.
Han Seo-yeon forced herself to breathe slowly.
"Sixth loop," Kang Ji-hoon repeated quietly.
She nodded once.
No more screaming.
No more panic.
This time, they observe.
The lights hadn't flickered yet.
The pale man was still normal.
Passengers were relaxed.
Everything looked harmless.
Ji-hoon leaned slightly closer.
"We track everything from the beginning."
Seo-yeon swallowed. "Starting now."
He checked the time.
"Three minutes until the announcement."
She scanned the cabin carefully.
The crying child.
The elderly woman near the window.
A businessman asleep.
The pale man scrolling through his phone.
Nothing looked dangerous.
Her head throbbed again.
A dull ache.
"Your headache?" Ji-hoon asked.
"It's worse."
He didn't look surprised.
"We're running out of time."
Before she could respond—
The announcement crackled.
"Attention passengers— please remain calm. Due to an unexpected—"
Static.
Same timing.
Exactly the same.
Ji-hoon's eyes moved toward the ceiling.
"Listen."
Seo-yeon focused.
Under the normal train noise—
There was something else.
A faint metallic ticking.
Her stomach tightened.
"Do you hear that?"
"Yes."
They moved slowly toward the middle of the cabin.
Not rushing.
Not drawing attention.
The ticking wasn't loud.
It was hidden under engine vibrations.
But it was there.
Below them.
Under the floor.
Ji-hoon crouched slightly, pretending to tie his shoe.
His hand pressed against the metal flooring.
The ticking felt closer here.
"Not front," he murmured. "Not back."
"Middle?"
He nodded once.
Seo-yeon's heartbeat quickened.
"If it's under the train…"
"We can't access it from here."
The pale man suddenly stood up.
Both of them froze.
But he only walked toward the restroom.
Normal.
Not attacking.
Not convulsing.
Seo-yeon felt dizzy again.
Her vision blurred for a second.
Ji-hoon caught her elbow before she stumbled.
"Focus."
"I am," she snapped softly.
But her body felt heavy.
The ticking grew slightly faster.
Her chest tightened.
"Can we warn the driver?" she whispered.
"We tried before."
"Yes, but not calmly."
He stood upright.
"Stay here."
"What are you doing?"
"I'm going forward."
"You don't have time!"
"I have enough."
He moved quickly toward the connecting door to the next cabin.
Passengers barely noticed him.
Seo-yeon stayed where she was.
Listening.
Tick.
Tick.
Tick.
Her breathing became uneven.
Her skin felt hot.
Something wasn't right.
The train shook lightly.
Earlier than usual.
Her eyes widened.
The timing shifted.
Ji-hoon returned faster than expected.
"They won't open the control cabin."
"Why?"
"Security protocol."
The ticking sped up.
Her pulse matched it.
"If we can't stop it—"
"We change the timing."
Her brows furrowed.
"How?"
He looked at the emergency brake handle again.
Then at the clock.
"One minute earlier than usual."
The floor vibrated more aggressively.
Seo-yeon's chest tightened painfully.
Her head spun.
Ji-hoon grabbed the emergency lever and pulled with full force.
The alarm screamed.
Unauthorized access.
But this time—
The train jerked slightly.
Not a full stop.
But a forced resistance.
Passengers shouted.
"What's happening?!"
The ticking went irregular.
Then—
Stopped.
Seo-yeon's heart skipped.
Silence.
For half a second—
Nothing happened.
Hope flashed through her chest.
Ji-hoon's eyes narrowed.
"Too quiet."
The red lights activated instantly.
The emergency announcement tried again—
"Emergency protocol acti—"
The explosion didn't come from beneath.
It came from ahead.
A massive shockwave from the front cabins tore backward through the train.
Like dominoes.
The blast hit Cabin C seconds later.
Fire swallowed the aisle.
Seo-yeon's scream never fully left her mouth.
Darkness consumed everything.
—
She woke up choking.
Cabin C.
Seventh loop.
Her body felt weaker again.
Her hands trembled without control.
Ji-hoon wiped fresh blood from his nose.
This time—
It didn't stop immediately.
Seo-yeon stared at him.
"It changed."
"Yes."
"The bomb reacted."
"Yes."
Her breathing grew shallow.
"It's adapting."
Ji-hoon looked at her seriously.
"No."
He paused.
"We are."
The announcement began again.
Seo-yeon closed her eyes briefly.
If the bomb's location shifts…
If the timing shifts…
If their interference changes the pattern…
Then this wasn't just planted explosives.
Someone was monitoring.
Someone was adjusting.
Someone was watching.
Ji-hoon's voice dropped lower.
"We're not alone in this loop."
The lights flickered.
And this time—
Seo-yeon felt it clearly.
They weren't just trying to stop a disaster.
They were inside a system.