Artemis- Hidden Vault Door

“Foaly. I’m going to . . . Owww!”
“There. That’s the  ray on.”
Mulch squinted at the safe. It was incredible. He could see right into
the works. Tumblers and catches stood out in shadowy relief. He blew on
his hairy fingers and twisted the combination dial. In seconds the safe lay
open before him.
“Oh,” he said, disappointed.
“What is it?”
“Nothing. Just human currency. Nothing of value.”
“Leave it,” ordered Root. “Try another room. Get going.”
Mulch nodded. Another room. Before his time ran out. But something
was niggling at him. If this guy was so clever, why did he put the safe
behind a painting? Such a cliché. Totally against form. No. Something
wasn’t right here. They were being duped somehow.
Mulch closed the safe, swinging the portrait back into position. It
swung smoothly, weightless on the hinges. Weightless. He swung the
picture out again. And back in.
“Convict. What are you doing?”
“Shut up, Julius! I mean, quiet a moment, Commander.”
Mulch squinted at the frame’s profile. A bit thicker than normal.
Quite a bit thicker. Even taking the box frame into account. Two inches.
He ran a nail down the heavy cartridge backing and stripped it away to
reveal . . .
“Another safe.”
A smaller one. Custom-made, obviously.
“Foaly. I can’t see through this.”
“Lead-lined. You’re on your own, burglar boy. Do what you do best.”
“Typical,” muttered Mulch, flattening his ear to the cold steel.
He twirled the dial experimentally. Nice action. The clicks were
muted by the lead; he would have to concentrate. The upside was that
something this thin could have only three tumblers at the most.
Mulch held his breath and twisted the dial, one cog at a time. To the
normal ear, even with amplification, the clicks would have seemed
uniform. But to Mulch, each cog had a distinctive signature and when a
ratchet caught, it was so loud as to be deafening.
“One,” he breathed.
“Hurry it up, convict. Your time is running out.”
“You interrupted to tell me that? I can see now how you made
commander, Julius.”
“Convict, I’m going to . . .”
But it was no use. Mulch had removed his earpiece, slipping it into
his pocket. Now he could devote his full attention to the task at hand.
“Two.”
There was noise outside. In the hall. Someone was coming. About the
size of an elephant by the sound of it. No doubt this was the man mountain
that had made mincemeat of the Retrieval Squad.
Mulch blinked a bead of sweat from his eye.
Concentrate. Concentrate. The cogs clicked by. Millimeter by
millimeter. Nothing was catching. The floor seemed to be hopping gently,
though he could be imagining it.
Click, click. Come on. Come on. His fingers were slick with
perspiration, the dial slipping between them. Mulch wiped them on his
jerkin.
“Now, baby, come on. Talk to me.”
Click. Thunk.
“Yes!”
Mulch twisted the handle. Nothing. Still an obstruction. He ran a
fingertip over the metal face. There. A small irregularity. A micro keyhole.
Too small for your average lock pick. Time for a little trick he’d learned in
prison. Quickly though, his stomach was bubbling like stew in the oven,
and the footsteps were getting closer.
Selecting a sturdy chin hair, Mulch fed it gently into the tiny hole.
When the tip reappeared, he pulled the root from his chin. The hair
immediately stiffened, retaining the shape of the lock’s interior.
Mulch held his breath and twisted. Smooth as a goblin’s lie, the lock
opened. Beautiful. At moments like these, it was almost worth all the jail
time.
The kleptomaniac dwarf swung back the little door. Beautiful work.
Almost worthy of a fairy forge. Light as a wafer. Inside was a small
chamber. And in the chamber was ...
“Oh, gods above,” breathed Mulch.

- Artemis Fowl, Chapter 7