Wufei is staring at the knife, and his own hand, as if they were strange artifacts of an alien world. Perhaps they were; perhaps this was all a nightmare, a terrible, black-edged dream. Instinct and training both demand that he pull back the blade, yank it free, let his target bleed out— Wufei resists muscle memory with a strength born of desperation, letting go and stumbling back, eyes too-wide, goggling with fear and horror.

"Duo," He says, because he doesn't have any other words, scraped thin by hollow shock, "Duo."

Everything he loves, he kills. There is blood rising around the narrow centimeter of steel protruding from Duo's chest, and some unfeeling part of Wufei is detachedly registering the presumed mass and position of the blade. He reaches out again, smearing trembling hands as he braces Duo by the shoulder and arm, guiding him to the floor before he falls. It is a death sentence; if they had access to surgeons and transfusions and all the miracles of modern medicine it might still be that. Here? Now? In this?

"I've killed you," He says, because it is the truth, the cruel mercy of entropy itself, "I'm sorry. I didn't mean to— There's no excuse. I moved without thinking, and I killed you."