Skin is human's largest organ. Skin acts as a waterproof, insulating shield, guarding the body against extremes of temperature, damaging sunlight, and harmful chemicals

But skin doesn't protect people from a strong radiation. Jim can already feel his skin dying along with his slowing internal organs. He drags himself to the door of the decontamination chamber and leans against it.

Jim doesn't know how long he lies there thinking, that this is it. He's going to die here. He's only twenty-six and he's going to die in a spaceship's decontamination chamber from a radiation poisoning.

He looks up when he hears footsteps. Spock. Scotty must have comm'ed him. He draws his strength and reaches a hand to close the door to the radiation chamber.

The average human heart beats 72 beats per minute.

Jim can feel his heartbeat slowing.

"I'm scared, Spock. Help me not to be."

Slowing, not quickening like it usually does when he sees Spock.

"How do you choose not to feel?"

He knows it's a lie. Of course he does. He knows how passionate Spock can be. Has often dreamed of that passion focusing on him, his heart beating furiously in his chest. His heart, that was so strong and so, so young, is now dying.

"I do not know. Right now I am failing."

Tears. He has never seen Spock cry. Not even after the Vulcan-that-was.

The human body contains nearly 70 percent of water.

He wonders how large that percentage is on Vulcans. Much smaller, he would assume, because Vulcan was so hot and full of red sand. He can still feel the heat and the wind that whirled around him when he and Sulu fell from the red sky at bone-crushing speed.

Since Jim was eleven and he jumped from that car (for a second it had felt like he was flyingflyingflying) he had been sure that he was going to die that way, falling. That someday he was going to burn his wings and fall from the sky.

Spock burns like his home-planet did before it collapsed on itself. The emotions inside of him burn him and tear him, making it hard for him to breathe. Jim has seen it and understood, because he has also felt that way so long. Uhura tries to understand but she has never really gotten Spock like Jim has, even if Jim sometimes gets frustrated and slashes out on Spock. Spock is like the fires of Vulcan and he cannot contain much water.

"I need you to know why I went back for you."

Jim remembers the panic he felt when he thought that he was going to lose Spock. He remembers listening to Spock's calm voice over the comm and thinking that fire cannot kill Spock, because fire cannot kill fire. He remembers asking Bones what Spock would do ("he would let you die") and believing his answer. Now he's not so sure anymore, when he watches Spock on the other side of the glass, crying and looking like he wants to claw his way in.

"Why I couldn't let you die."

He remembers the relief and the overwhelming joy he felt when he saw Spock standing on that transporter-pad. He didn't regret it for a minute. Not even when he lost his captaincy. He was only angry because he was going to lose Spock too. He couldn't lose Spock, not ever.

Spock really shouldn't be wasting what little water he has. Wasn't it illogical to waste something so important? But small teardrops keep on falling from the Vulcan's dark eyes when Spock answers.

"Because you are my friend."

Jim reaches a hand, desperate to wipe away the tears before they put out the fire inside of his friend. But his hand meets only the cold glass of the door separating them.

90 percent of the human body origins from stardust.

Jim finds it comforting, really. Because even if he can't see the stars right now he has pieces of them with him. Dying with him. He may not die in a blast in space, like his heroic father, but he'll still take the stars with him. And his crew is safe. Their ship is safe. Spock is safe.

He wonders if there will be stars there, wherever he is going. He hopes so. He arranges his hand, trying to match the shape of Spock's hand. Ta'al. The Vulcan greeting turning to a goodbye. He looks at Spock straight in the eyes, takes a deep breath and tries to tell the real reason why he couldn't let Spock die. Not inside of that volcano, not now.

"I lo-..."