There is a distinct sensation of cold. It permeates every word so painstakingly forced out and rushes bitter into Spock's lungs. If he did not know the exact density of one mole of the Enterprise's atmospheric air content (17.8553 g/mol) the conclusion would have been that the molecules themselves were growing heavy. Spock was in near-optimal health, so why was there a pang in his side and a tightness in his throat? Most illogical.

The glass under his sensitive fingertips was ever colder. It shouldn't have been. It should have been the temperature of the captain's own hand (37.334 degrees centigrade). Instead this interloping pane of glass kept him 3 cm—far too great a distance—from the shaking fingers sloppily assembling themselves to form the ta'al. Cold. Much too cold.

And worst of all, those blues eyes. The warm cerulean that held the heat and intensity of a hundred stars (impossible, they were at most 4.12 centimeters in diameter and could not possible contain even one gas giant-) were frigid as the vacuum of space. It was so wrong; Jim—the captain, above all he was warm. His smile and his voice and his demeanor and his conduct—the way he never ever left a crewman behind if there was a 0.47% chance of saving him—Jim Kirk was a warm being.

The prickling in the corner of Spock's eyes has melted into a trail of salt water. Unacceptable. Vulcans do not cry.

But it is not nearly as unacceptable as the way the captain's hand falls or the shuddering stop in the rise and fall of his chest.

Anger.

He's felt it before: in heated arguments with the captain over logical courses of action, watching as his own hand closes around the throat of the very same man, staring down the one responsible for his mother's death, and if he'll admit to it: standing in front of the Vulcan Council as they ridicule his descent.

It is a heat in his stomach that never ceases and the roar of blood in his ears.

Guilt.

Another familiar emotion: staring at the empty transporter pad that should have held the most important woman, looking at the shocked faces on the bridge and into the eyes of the man he nearly killed, hearing the pain in Nyota's voice as he realizes he's hurt her.

It is in the way he clenches his jaw and the catch in his voice.

Sorrow. Oh, and it is the worst. The ache of a thousand bonds broken and the telepathic death cries of millions of his people, the hand that closed around air, and in the eyes of his father.

It is the part of him that wants to scream in anguish and tear the flesh of the monster responsible.

And Surak, does it feel good to hear the crunch of bone and the pounding of his own heart and the whistle of the air around him. Logic has completely abandoned its hold on Spock, and his blood boils and sings with every pained sound from Khan. You can't even break a rule, how can you be expected to break bone?

Wrenching Khan's arm free of its socket holds a morbid satisfaction.

"Spock!"

Fierce pleasure rises up with every time Spock's fist collides with his enemy's visage. He cannot be forgiven, never. For right then there is no crime more horrible than depriving the world of the light that is James Tiberius Kirk. There is no line in Starfleet regulations that condemns a man to death without trial.

"Spock! Stop!"

The voice is only one more distraction in the torrent of noise. Again and again and again he slams all of his rage into the man that took everything. Spock can feel his own fingers break, but the pain too dulls into the background. Do you know why I went back for you?

"Spock!"

You know, I'm going to miss you.

"It's the only way we can save Kirk!"

Kirk.

Jim.

Because you are my friend.

And he cannot stop his blow from connecting with Khan's skull. Cannot erase the sickening crunch of skull and spray of blood. His own roar of pain coupled with Nyota's shriek.

"NO!"