It would be simple enough, in theory. It was merely a question of finding the proper ratio between surface area and volume in order to reduce conduction. All he needed to do was transmute the metal in question into thin strands and then induce rapid oxidation.
He had the element of surprise, after all. Fullmetal would never see it coming.
"Colonel..." His ever-vigilant lieutenant murmured a warning against his right side. She didn't know exactly what type of array he was sketching, but she knew him well enough, he supposed, to guess it wasn't anything good.
He set down his pen. He wasn't certain of the type alloy that the boy's mechanic used to manufacture his limbs, although he supposed could do a quick flame test to discern the components...
Fullmetal regarded him obstinately, but a hint of wariness flashed in the boy's cat-like, golden eyes. "Well?"
Roy smiled pleasantly. "Thirty thousand sens."
"Your expenses. For one week." Roy's smile strained at the edges, but he kept it plastered on through sheer force of will. He would not lose his composure over this. "Thirty. Thousand. Sens."
The young alchemist blinked slowly, then grinned. "What does that have to do with my report, you bastard?"
If he'd still been holding the pen it would have snapped in two.
"Edward," Riza chided gently, "Just because you fill out an expense report doesn't mean that the military will automatically cover your expenses." Riza handed the boy a folder. "You need to sign and initial these forms. We worked it out that most of the funding came from your research grant, but no amount of fiduciary gymnastics could possibly include some of the items, so their prices will be deducted from your next paycheck."
Roy sighed. Bless her, in the space of five minutes she had prevented him from potentially setting the office ablaze, staining his freshly dry-cleaned uniform with ink, and leaping over the desk to strangle his subordinate. He allowed his gratefulness to fuel his smug cover. "Really, Fullmetal. Toys?"
The boy clenched his fists. "They weren't for me."
"No! He doesn't..." Fullmetal hung his head. "There was an orphanage, all right, you nosy bastard? The town we stopped in was having a festival, but the kids couldn't...they didn't...oh whatever, as if I even have time to use my paychecks, anyway."
Roy, not for the first time in his life, felt like an utter, complete jackass. "Ah."
"Why do you care what I spend my money on, anyway? Most of the time you never even glance at the reports."
Most of the time, he wasn't facing an extensive audit, either. He straightened the documents on his desk while he thought about his situation.
"Fullmetal, please hand the folder back to Lieutenant Hawkeye. You'd do well to watch your budget more closely from now on." The young man frowned, but Roy cut him off with an imperious wave of his hand. "You're dismissed."
"That's it?" Edward, no, Roy corrected himself ruthlessly, Fullmetal. If he kept using that heavy name, perhaps he would forget seeing the boy, so small, swathed in bandages and nearly bereft of hope. He was a soldier now. Not a child.
Fullmetal looked as confused as Roy felt. "That's it. Unless you're waiting for me to change my mind and render ten thousand cens due immediately?"
The young alchemist was out the door before he could finish his sentence.
Riza stared at him for a long moment after his office door slammed closed. "You can't justify these expenditures in the audit, regardless of their good intent."
She tilted her head to the side. "What do you plan to do?"
Roy ran his hand through his fine hair and heaved a sigh. "I suppose I can cover some of his costs, this one time."
Riza attempted to hide her smile behind Fullmetal's folder, but he saw the edges of her eyes crinkle. "You're getting soft-hearted with age."
"Just poorer," Roy sighed. "Maybe with my next promotion..."
Riza set the folder on his desk. "This should give you an incentive to work more industriously, so you can get that promotion." She left briefly, and returned with a stack of files the size of a small tree.
"As hard-hearted as ever, Lieutenant."
"Thank you, sir." She paused at the doorway. "Should I tell your date you're too poor to take her out tonight?"
He chuckled. "Tell Elizabeth I wouldn't dream of her making an excuse to skip out on dinner with me."
"Perhaps you should eat in."
He grinned. "Perhaps we should."
"It would give you plenty of time to finish your paperwork at home."
His grin faded. "Slave driver."
She simply smiled.