They don't put her under until halfway through the operation.
It is a lesson, they tell her, that she must learn; a punishment, for striking Gamora's face so hard when she'd finally thought she'd had the upper hand in their duel. Gamora is Father's favorite, they say, so using unwarranted force against her is tantamount to attacking Father.
Nebula hadn't cared about that, at the time; she'd just wanted to see Father's perfect little warrior bleed a little.
She'd still lost, of course she had, but she had managed to bruise her 'sister's perfectly pretty face so badly the left half of her face had swollen to a yellowish bruise before the match was over.
Gamora came away with a victory and a vibrant bruise that would heal in time.
Nebula was dragged away with a loss and a new modification scheduled within the hour.
Her ribcage is afire, hands and blades sinking into her guts at random intervals, in and out, and she can do nothing to stop them.
They ignore her shrieks of agony, chide her like a disobedient child when she spasms hard against her restraints, clean up the blood pouring from her heaving chest with a bored detachment that is common for the Chitauri people.
She screams threats of torture and murder at deaf ears, and only manages to wrench one hand free of the cuffs holding her to the table before a deep baritone voice relents.
"You may knock her out, now."
She jerks hard again, eyes rolling in her frothing desperation to find him.
Father stands in the doorway to the operating theater, face a stony mask of disapproval and arms crossed in front of him.
"You're only making this worse for yourself," he remarks idly.
"Fuck you!" Nebula barely manages to snarl before the surgeon injects something, and everything goes utterly, blessedly dark.
A/N: I hope and pray that Nebula is the one to kill Thanos in A4.
~Persephone