Starscream had already settled himself on the operating table by the time Arcee fully processed what he was asking of her. His aerial alt mode was the singular advantage that he had over the Autobots, and only with him losing it did they stand any chance of defeating him in a one-on-one battle. More specifically, it was the only thing that made him Arcee's own equal in terms of weaponry.
And that was all assuming she didn't end up killing him during the procedure- accidentally or not.
"And why should I help you get an alt mode back when I can't even use mine?" Arcee asked, crossing her servos in refusal of the scalpel Starscream held out towards her. His talons gripped the handle harder, scoring grooves into it as he growled.
"This is not the time to be petty, two-wheeler. Either suck up your bitterness and help me, or get used to being under Megatron's claws for the rest of your short life."
As overdramatic as the statement was, Arcee's will to survive the remainder of the war intact outweighed her need to see Starscream suffer. Still, even if she wasn't operating on an enemy, she was no medic. Anything beyond a simple field patch up and scratch buff was way beyond her. "Do you really want someone like me slicing you open?"
Starscream's expression curdled. "Believe me, you wouldn't be my first choice, but you're the only one I have. Just do exactly as I say, unless you actually like having those restraints stuck on you." Though his snarl was convincing enough, it couldn't mask the tremor in his vocaliser; the one that showed he was just as nervous as she was. He knew how dangerous she was, how quickly she would offline him given the chance, yet he was the one literally offering her a knife to gut through him.
He really was desperate, then. Arcee finally took the scalpel from him, rubbing her digits over the marks left by his claws as he lay back on the tilted table.
"Now, there's two ways to proceed…" Starscream hissed stale air through both vents and olfactories. "I can either endure an incision through my side, directly cutting into where my T Cog should be, or… accessing through my chest, since the cog goes right underneath the spark chamber. Each have their own range of complications and countless things to go wrong, so it really makes no difference which one you choose."
Arcee's optics flicked to both his chest, rising and falling slowly with his stilted breaths, and the point above his hip where one of his talons tapped. "Which is less dangerous?" she asked. Though this opportunity to terminate him would never come again, she wasn't so blinded by revenge that she'd jeopardise any chance at ending the war early.
Starscream stared at her, as if trying to figure out whether she actually was planning to kill him. "In the short-term, the first one, though there's always the possibility of the incision becoming infected. So if you want a chance of me dropping dead later, I'm sure you'll enjoy that method." He flashed a knowing smirk at her, obviously goading her into some sort of confession that, just this once, she needed him alive.
She weighed up the options for a few long moments, staring at the blade in her hand and Seeker-turned-sacrificial lamb in front of her. "I'll risk going through the chest," she decided.
Starscream's optics widened in surprise, and his mouth flattened into an impartial line. "...Very well." He turned his helm so he was staring at the ceiling, and air rattled in and out of his vents. "When I open my chest plating, I'll indicate where to cut into."
Arcee's optics narrowed in confusion. "Aren't you going to induce stasis?" That had been her assumption, that Starscream would give her all the directions before hand, but he stubbornly shook his helm.
"And let you run off to leave me here? No, I'll happily take my chances with the pain instead." That he would endure the waking agony about to follow just to make sure she stayed put said a lot more than he would have meant to, Arcee couldn't help thinking, but she let the scalpel blade cut into her palm to chase the notion away.
She watched as his chestplates slid apart from each other and folded outwards, baring a crystalline chamber around a pulsing, yellow-tinged orb. She'd never seen a spark aside from her own, which swelled up for some reason at the sight of another, and she'd half-expected his chamber to be a dull husk, the ember inside it burned down to an ugly lump of coal. But the glowing sphere was as bright as Praxus' midnight skyline, like Primus had plucked a star from the cosmos and placed it inside every one of his creations. And it was far too beautiful to belong to someone like Starscream.
Still snared in awe, Arcee only managed to move herself when her vocaliser jolted first. "Your spark doesn't match your optics," she noticed. Though the diffused light fit with his reticules, it didn't explain where the crimson of his irises came from.
"Seekers transmit the light differently," he explained with a rough edge of impatience. "Now hurry up already. Just cut right across the floor of the plating."
Squinting against the glare from his chamber, Arcee almost didn't see the grey protoform that separated his main chest armour from the thick cables that made up his abdomen. Transferring her scalpel to the other hand, she still struggled to maneuver the blade parallel to the taut metal skin without brushing her wrist against the chamber taking up so much space. The knife eventually managed to cut into the metal, finding purchase in the slice it made as Starscream hissed through a groan above her. Her concentration wavered, optics flicking up to his helm, and she only continued when he gave a small nod. The blade glided with surprising ease through the protoform underneath it, welling energon in its wake, and Arcee was halfway across his chest when he tensed and, half a klick later, his vocaliser screeched when her hand was hit with a sudden burst of warmth.
"DON'T-!" Whatever she did to inevitably frag up, Starscream let the whole planet know of it from the shriek that echoed through the Harbinger's hull. Arcee almost dropped the scalpel inside him as she instantly snapped away from his chest.
"What, what happened?!" she asked, scanning the cavity for anything wrong with it and trying to ignore the fresh sting on the back of her hand.
"Oh, nothing really, you just almost made my spark core collapse in on itself!" Starscream panted as Arcee noticed his spark spasming hysterically, as if trying to leap out of his chamber, and his wings fluttering like they were about to fly him off the table.
"Well, I didn't do it on purpose!" she protested, splattering energon drops on the floor as she threw her servos out.
"I know you didn't!" Starscream yelled back, staccato breaths whistling between his clenched denta. "Mech sparks… contract away from foreign contact…" he explained, and Arcee realised her burning hand must have gotten too close to his thin chamber core. "Hurts like the fragging Pit, but... just keep working. Use the forceps to... keep the incision open. I need to... distract myself..."
Arcee reached across to the equipment for the barbed tongs she'd spotted earlier, nudging against the golden T Cog itself and wondering just how she was supposed to jam it inside him. She shook her helm, pushing the doubt aside for when it would be needed, and grimaced as she inserted the forceps into the left side of the bleeding cut. As she worked, Starscream hummed past his gasping vocaliser; some sort of melody she didn't recognise but would have enjoyed hearing back on Cybertron. The lilt was only interrupted by another set of pained instructions and an occasional rumbling groan as his nodes rebelled against being lacerated and stretched.
After the stress of preparing his internals for accepting the transplant, actually setting the cog inside him was graciously simple. All it took was putting it in the right place, and making sure her energon-coated digits didn't slip. The organ fit perfectly into its once-empty space, and Starscream sigh was a shudder of pulled her hand out, the energon covering it already drying in the cold air of the ship, and noticed the Seeker's spark had settled in a strange state of ebbing calm.
"What was that tune you were humming?" she asked, curiosity overriding her own sense of relief as she wiped her servos on one of the ship's structural supports.
"The last stanza of 'Daedalus' Descent'," Starscream answered, dimming his optics to a dim glow through his lowered lids. "It's a Seeker poem, written some time before the Age of Wrath. Most of it was still lost during the Golden Age." As if talking had helped relieve the aftershocks of pain still rooted in his systems, he managed to prop himself up on his elbows and start closing his chest plates back over.
"Shouldn't you patch the wound up first?" Arcee asked, flicking the last of the fluid off of her digits.
Starscream shook his helm wearily. "No, no, I have a nickel allergy, and field kits are full of the damn stuff... an internal wound won't get infected, anyway." His plating shuddered back into place, and he fingered the armour seams to make sure they were as sealed as they looked. "Arcee... never become a medic," he pleaded.
She scoffed, almost wishing she'd just pried that beautiful spark of his out. "You're still alive, aren't you?" she pointed out.
Starscream unclenched his denta so he could smirk at her. "True… at least you didn't try to carve my fuel pump out to sell on the black market, like a certain red doctor once did."
"A thank you would be nice as well," she muttered, folding her servos over her chest as the Seeker pushed himself back onto his shaky peds and prodded around the spot where his new cog resided. He stared sidelong at her, regaining slow control over his vents with limp wings and an indecipherable expression.
"...Thank you, then," he eventually huffed.