Flint had been standing so unnaturally still for so long that his presence barely registered to the working dwarves now. When he’d first arrived in the room and took his position nearby, they’d gone silent and tense under his curious observation. Now they sang in their guttural manner while they worked, and their tools were as musical instruments. Flint wondered how many songs they knew for laying bricks, if the rhythms were all the same or if some were faster.

He didn't ask. Just now he was listening to vibrations in the steel infrastructure lining the elevator shaft behind him. It was raining up there.

The rhythmic scrape-slap-tap ceased and the song finished. Flint opened his eyes again, hours after he’d closed them. He watched as the workers cleaned and packed away their tools and gathered up buckets of unused mortar. The foreman nodded to him, and he nodded back.

They’d built a large archway to nowhere - a frame really - settled against a side wall of the vestibule. It was the largest exterior wall in the vault, with solid earth behind it. Flint removed himself to the wall opposite this archway as his soldiers began to file in, chatting amongst themselves. They snapped to silent professionalism when they realized he would be observing their work now, too.

The captain took up a position near Flint, and gave orders.

Twenty-two carts were wheeled into the vestibule, two at a time, and then elongated black tubes were produced and mounted to the carts one at a time and fixed in place by bolts. They were assembling cannons, polished and fresh, and the junior alchemist inspected each one with a parchment in hand, confirming its worthiness with dozens of careful check marks. When every cannon was finished and confirmed, the master alchemist came through with his own inspection.

Roxanna arrived as the soldiers were bringing in the ammunition.

“Has he come back?” she said, following Flint’s gaze to the work being done.

“No,” Flint said. “But he will.”

“I don’t doubt it,” she said, “but how can you be sure? He got what he needed from us. He could just as easily go himself, or with this man-breaker you keep talking about.”

Flint nodded. “He could, but he hates Lye. Hates him. You understand that, if anyone in the world does. He will use every tool at his disposal to hurt the man as badly as he can. I am a weapon, why leave me unused?”

Roxanna made a thoughtful sound. “I wouldn’t want to risk someone else getting the satisfaction.”

Flint grinned. “I think you would permit that risk to lessen the risk of your prey escaping.”

She nodded. “Lye is dangerous. This could still go poorly.”

The work was done. The archway was finished: a door to nowhere, with twenty-two cannons expertly arrayed to fire into it. The explosive ammunition was set up beside each cannon, ready to be loaded, and the cannoneers were even now preparing to take up positions. The crack riflemen would line up behind the cannons, and each would have three double-shot rifles and a single-shot pistol each to unload into that empty doorway. Radek was sharpening his blades now, and Roxanna was ever-ready. Flint was of a mind to leave her behind in case things did go poorly - his empire would need running, after all - but he knew she would not permit it.

“If it goes poorly for us,” Flint said, “I’m confident we can ensure it goes poorly for them, too.”

Roxanna was silent for a time.

“Well it won’t go any-which-way without the half-elf’s magic,” she said impatiently.

“He’ll come,” Flint said. He closed his eyes again, and turned his attention back to the rain somewhere far, far above them.