It apparently wasn't widely known, but Roy Mustang had excellent hearing. Being alert was an important soldier's skill, after all, and he prided himself on mastering most of the military arts. So although the small group gathered across the room wasn't aware of it, Roy knew that they were whispering about him.
"Do you think it'd be okay to ask him?" A particularly loud whisperer's voice stood out.
"…but it might be a really bad idea!"
"Hey, we should get the Fullmetal kid to ask!"
"Get me to ask what?"
Ed's voice, as usual, was loud as day, but he also heard very well, especially if his name was mentioned. Roy knew that Ed hated these snarky gatherings, and that he had only come because Roy had personally asked him to. He was probably skulking over there near the kitchen to see if he could transmute some food for himself on the sly before dinner was served. The thought made Roy smirk into his coffee.
"Well, aren't you going to tell me?" If Ed was anything, he was persistent.
At that point, the conversation must have moved into the kitchen itself, because Roy wasn't able to hear anything else. Soon, however, an unmistakable noise reached his ears: Edward's ringing laughter. It was a sound that usually made him smile, but at this moment, it made him wary. Whatever they were planning certainly involved Roy himself, and if he knew Fullmetal, the chances of it being something honorable and decent were slim to none. Roy set his resolve: he would stay put and refuse to participate. After all, this was a distinguished military gathering. The last thing he needed was for Edward to make a scene.
The waiter came by asking if he wanted more coffee, and Roy proffered his cup. It had been several minutes and Ed still hadn't come out of the kitchen. Maybe there was a back door? Perhaps it was time for Roy to make a graceful exit, before the inevitable happened? But maybe that was what they wanted him to do?
Roy's fingers tightened on his coffee cup. This was infuriating. There was absolutely no reason why Colonel Roy Mustang's decisions ought to be influenced by a slew of caterers and a brat, however attached he was to said brat. It was patently ridiculous. No matter what happened, Roy would simply sit here, he told himself, maintain his calm and decorum, and let Ed look stupid for playing his silly games. Damn him.
All of a sudden, he felt something subtly shift in the air. Alchemy. Edward, what are you doing…? Roy didn't like this. Despite the fact that he told himself a hundred times a day that he didn't care, he worried about Edward nevertheless. Fullmetal was generally pretty good at taking care of himself, but he was still young and could be fooled easily. What if those men he was talking to weren't just waitstaff, but secret homunculus spies? And now Ed was having to fight his way out of there by himself…?
Put it out of your mind. Ed's probably just transmuting himself some grilled steak. Not at all unlike him. If he needs help, he'll call -
"ROY! I need you!" Ed's voice echoed from the kitchen. Crap!
Just then, the man who was apparently the head chef came bursting out of the double doors, all aflutter. "Colonel Mustang, Sir! Your leetle boy 'eez in big trouble!"
Everyone in the room turned to look at Roy. First thought: Edward, I'm going to kill you. Second thought: I hope he's not in any real danger. Third thought: 'My little boy?' Just what kind of rumors have been going around here…?
Roy couldn't help it: he leaped up and ran into the kitchen. When he arrived, the last scene he was expecting to see met his eyes. Ed was in the center of a huge, glowing array, surrounded by giant… worms? snakes? Some sort of yellow wormlike things were apparently attacking him. The weird things were glowing with blue alchemical light, as if they had just been conjured… but by whom? Roy's immediate gut reaction was to scan the room for the rouge alchemist, but he could see no one.
Ed was shouting, "Roy! It's like a hydra! You've got to hit them with fire: it's the only thing that's gonna take 'em out!"
Something about this was very wrong, but nevertheless, Roy immediately shifted into battle mode. Snap, snap! The worms deflated to nothing, completely helpless in the face of the Flame Alchemist's prowess. Fss! Splish! Sizzle! One after another, he brought them all down. There were so many of the things, 40 or 50 at least… where the heck were they all coming from? Roy twirled around, sending fire from both fingertips like a deadly gypsy dancer. He couldn't help it: his face was flushed with pleasure. The feeling of fire moving through his body exhilarated him like nothing else. Maybe I'll have to thank Ed after all. After I kill him, that is.
He heard a clap and turned to see Edward altering the array. Each one of the now crispy brown worms descended neatly into a small, round… dish? What exactly was going on? Roy sniffed. The air was pungent with the smell of… caramel. Oh no. Don't even tell me…
Suddenly, the room exploded with applause. Roy looked around and belatedly realized that he had had an audience: a large crowd of military personnel stood outside the kitchen doors, waving and cheering.
The haughty chef stepped forward and announced: "And for our dessert theez evening, I present: Flame Alchemist Crème Brûlée!"
Edward was sitting in the middle of 50 dishes of now perfectly carmelized crème brûlée with a ridiculously smug grin on his face. The grin vanished quickly as Roy pounced, but Ed was too quick; he dove right under people's legs and out the door.
Roy held up his still-gloved hand and the crowd parted immediately; he caught a glimpse of Edward's red coat flickering past the doors on the opposite side as he rushed after him.
"You just wait till I get my hands on you, Fullmetal!"
Ed's gleeful laughter rang through the stairwell. "You'll have to catch me first…!"