Lin Yu hadn't initially planned to tell Furbollo all the information he possessed. 

Though he'd resolved to eliminate this 'Detective' if suspicions arose, Lin Yu found Furbollo surprisingly useful as a tool during their interactions.

This 'Detective' genuinely had skills - he was even sharper than Lin Yu had anticipated.

Thus, Lin Yu became somewhat reluctant to kill him.

Therefore...

Lin Yu changed his strategy.

He decided to be more "honest" with Furbollo.

Regarding anything unrelated to his promotion mission, Lin Yu could afford complete transparency.

As for the dungeon information...

Lin Yu decided to process and reveal everything to Furbollo.

After omitting the "motives" and the reasons Vale Valetti trusted him, Lin Yu shared all currently known intelligence with Furbollo.

Trekking through the snowstorm, Furbollo examined the metal key while piecing together the situation's context.

"I understand... Combining this with the notebook we found, the events at 'Extreme Winter Mountain' represent a textbook case of technology-induced tragedy," Furbollo mused. "Some organization possessing 'advanced technology' had an accident here, creating a monster called 『Chate』 that caused numerous deaths..."

"Then some poor low-level employee from that organization was sent to investigate, discovered the truth, and unfortunately died here too."

"But he was luckier - he retained his consciousness. He's been warning you through dreams."

"This might also be protective, since that 『Chate』 creature's killing method is dream-related."

Lin Yu largely agreed with Furbollo's analysis.

"Exactly my thoughts... So now we need to reach that 'cave'."

Hearing this, Furbollo frowned.

"But are you certain 'Vale Valetti' is trustworthy, Doctor?"

"Remember... It's not just Players we need to guard against. Sometimes NPCs require caution too."

"Currently, both 『Chate』 and the deceased 'Vale Valetti' possess dream-invasion abilities. Even if he was kind in life..."

Furbollo trailed off meaningfully.

Lin Yu nodded. "I understand, Furbollo. I haven't fully trusted him either."

"But even if it's deception, even if it's a trap, I still want to investigate," Lin Yu exhaled softly. "Because we're running out of time."

"This is already our fifth day... But considering humans can't maintain 72 hours without sleep under such stress, we'll likely need to sleep once more."

"So this might be our 'second-to-last' period of consciousness."

"Of course... To simply clear the dungeon, we could ignore it and gamble that 『Chate』 won't kill us during our final sleep."

"But would you be satisfied with that, Furbollo?"

Lin Yu stared directly at him.

"Your will to survive is undoubtedly tied to 'uncovering the truth,' isn't it?"

"Same here - not understanding the truth would haunt me forever!"

He declared with contagious conviction.

Furbollo's expression twisted conflictedly at Lin Yu's words.

Finally adjusting his straw hat, he conceded: "You've convinced me, Doctor. I entered this 『Death Game』 precisely because of an unsolved 'cold case.'"

"That's just how I am - any sufficiently complex mystery left unsolved makes me physically uncomfortable."

"I'll take this risk with you - besides, such an intricate, deeply-hidden dungeon must offer fantastic rewards for 『Threading the Needle』!"

"Damn it all, if I can't solve this mystery after bringing out the 'Straw Hat,' that'd be downright embarrassing!"

Furbollo growled determinedly.

Lin Yu regarded him with understanding.

"I knew it - we're cut from the same cloth!"

He laughed.

Furbollo joined in the laughter.

"Never expected a doctor... to be just as crazy."

"But encountering a 'kindred spirit' does feel incredible."

As he watched Furbollo laugh, Lin Yu secretly sighed in relief.

"Success."

Furbollo was indeed brilliant.

When he'd produced the "Straw Hat" and claimed to enter "full-power mode," it wasn't empty boasting.

This 『Detective』 who'd cleared sixteen dungeons hadn't even been 70% serious about this one before.

But...

Precisely because of this, Lin Yu's current "performance" worked so effectively.

He understood exactly what this "genius" Furbollo desired.

For Lin Yu, deceiving "geniuses" became easier than fooling ordinary people once he comprehended them.

Because geniuses believe what they choose to believe.

"Might even use him to investigate the Psychological Society after escaping."

Lin Yu considered, though his focus returned to the current dungeon.

"Let's go, Furbollo - time to uncover the truth!"

"To that cave we go."

As Lin Yu spoke, Furbollo flashed a confident grin.

"Agreed. Based on my geological knowledge, this 'Extreme Winter Mountain' features typical folded terrain. Any cave capable of housing metal doors... was likely a large natural formation."

"Such caves usually form between two peaks... and within this dungeon's 'boundaries,' there are only two high points."

Furbollo declared triumphantly. Lin Yu nodded.

"Lead the way then."

"No problem, May - when I enter full-power mode, clearing dungeons becomes child's play!"

"That's precisely why I usually hold back - at full mental capacity, any dungeon loses its challenge!"

Furbollo boasted, then...

After trekking through the snowstorm for hours, Furbollo guided Lin Yu to the convergence point of two mountain peaks.

Standing amidst endless snow, staring at two exposed, barren cliff faces, Furbollo fell deep into thought.

Lin Yu looked at Furbollo and sighed.

"Not very impressive for 'full-power mode,' great Detective."

"Where's this cave of yours?"

Furbollo scratched his head vigorously.

"What the hell? This can't be right... This must be 『Chate's』 illusion!"