Blood wells around the dagger's point, staining Thor's armored tunic. And Thor's hopeful expression twists with pain, betrayal, loss.
And Loki...
...can't...
...think.
He stumbles back, a ragged scream ripping past his lips. His brain feels like it's cooking in his skull, bubbling, boiling, liquefying.
Half-hysterical with it all, he slaps his palms over his ears to keep his mind from spilling out, and Thor is watching, horrified, the dagger in his gut very much forgotten, as Loki sways like a drunkard, his own arms outstretched cautiously, as though to catch him. The thought alone, that stupid, stupid Thor would try to protect him still, even after he'd just thrust a blade through his torso, brought a giggle bursting forth, and with it, a viscous, black fluid that dribbled over Loki's lower lip. It tasted putrid. Like dark magic.
Groaning, Loki squeezed his eyes shut, ignoring Thor's panicked shouts, the screech and shriek of Dr. Selvig's machine ripping open the sky. Then he straightened, an arm clutched protectively over his stomach and a fist to his temple. Green eyes flew open.
Vividly, vibrantly green.
His gaze darted wildly, taking in his surroundings as though he'd forgotten where he was. There was a glint of recognition, a determined set to his jaw, and a flash of regret at the crimson spreading over Thor's armored tunic, the wound that did what poisonous words and attempted fratricide could not. Raising his voice, he called out to the outcropping above, "Shut it off, Dr. Selvig!"
Had Selvig not been bound to him by the Tesseract, he might not have heard his words over the cranking of the machinery, the whipping winds, the screams from those beset upon by the Chitauri below, and likewise, Loki might not have heard his reply. "I'm sorry," the brainwashed scientist shouted down, "but I can't disobey orders."
Liable to pull his own hair out, Loki made a noise of frustration. "Those were my orders!"
Thor was staring at him like he'd lost his mind. Maybe he had.
Maybe it didn't matter.
Loki tightened the grip with which he held the curved staff in his possession, knowing now what stone it carried. Now that he was aware, he could even feel its subtle attempts to reclaim its influence over him, the invisible, incorporeal tendrils that tugged and caressed in turns.
He shut them out, raising his own seidr like a protective shield over his thoughts. Focusing on that particular string that guided him to Selvig, he conveyed through the connection, I know about the failsafe. A spark of fear pierced the bond, the only evidence of Selvig's little resistance. In spite of the circumstances, Loki couldn't help feeling rather smug. That the human had honestly believed he'd performed an independent action without his knowledge was as amusing as it was hopelessly naive. Impatient, he continued, I've known about your little rebellion this entire time. And I don't care. Now, I am ordering you, Dr. Selvig, to do whatever it is you need to do to close that portal before your military, in its infinite wisdom, drops a nuclear device on this city that will destroy everything and everyone you hold dear.
Predictably, Selvig began fighting the influence of the stone, prioritizing the safety of millions of lives over its orders. He grabbed a piece of fallen debris and smashed the machine repeatedly, violently, screaming with both the physical and mental toll of the effort.
Meanwhile, Loki curled his lips, baring his teeth at the closing tear in the sky in a feral and vindictive grin. In vast waves, the Chitauri fell, sometimes even dropping from their suddenly inoperable crafts to plummet to the streets below. A little encouragement, the right motivation, and the invasion was over. Loki felt it when the connection between him and the doctor snapped, taking the resulting backlash like a slap, but not even the pain of the forcefully broken bond was enough to ruin his good mood now.
"What trickery is this, brother?" Thor's accusing tone dragged him down forcibly from his high, and he reluctantly looked down to face him, and the sight nearly broke his heart. There was again that hope gleaming in Thor's eyes, but it was shrouded in suspicion and doubt. To himself, Loki wondered if he had altered the course of events one second too late to preserve Thor's faith in him.
The thought made his throat go dry. "This is no trick, Thor." As he spoke, Thor yanked the blade from his side, grimacing. With an almost thoughtless flick of his wrist, Loki had the wound, already well on its way to healing, sealed shut. Not even Thor's flinch could phase him. After all, whatever pain he experienced now was nothing compared to the agony Loki had spared him. With a buoyant, airy feeling that resembled intoxication, Loki hoisted the staff above his head, "This is only the beginning. I am striking out the red in my ledger," and slammed it down on the tile, shattering the headpiece and sending the mind stone skittering across the floor, only to be plucked up by a cloud of amorphous magic, and tucked away into a pocket dimension, where no one but the trickster himself could reach it.
With that done, he brushed roughly past Thor, striding briskly into Stark Tower while heedless of the protests that chased his back. Not long after, the Avengers would find him sitting unarmed at the bar, three-quarters of the way through a tall bottle of the strongest whiskey on the shelf.