The moment Sam got to the car he turned around and ran back into the building. Dean wasn't following, and there was no way he could risk his brother. Not again. That was when the screaming began.
The sight that met Sam's eyes made his stomach drop, the panic paralysing his nerves for a few seconds. Two of the men were already floored and bleeding out. If they weren't dead already, it would only be a matter of minutes, if not seconds.
The hunter, stashing his gun in his back pocket, darted forward, just as the third man, Randy, collapsed to the floor, gurgling as he struggled for breath. Sam winced in remorse but didn't hesitate. His brother was losing control and fast, it was up to him to bring him back.
"Dean!" he got between the elder Winchester and the fourth man, hands clamping down on his brother's shoulders. But it was all too quick. Too sudden. Dean hadn't expected his brother to show up so fast. His eyes widened in realisation and panic, snapping out of his trance.
But it was too late.
Sam staggered and stumbled to the floor, hands pressed against the gaping wound that went from his abdomen to his chest in an attempt to slow the bleeding. His shirt, ripped from where the knife sliced him, was quickly turning dark red.
"Sam!" Dean's voice was thick with desperation as he dropped his weapon and threw himself down beside his little brother, "Oh God…oh god, Sammy. Sammy. I'm sorry."
He pressed on the wound as best he could, "You gotta hold on for me, you hear? Don't you dare go leaving me now."
Sam's breaths were harsh and faltering, but he still attempted to sit himself up, "Dean…"
"Hey, hey, take it easy. We'll get you out of here. We'll patch you up, you'll be good as new. And it's all gonna be alright," Dean's voice was desperate as he propped Sam up on his knees, "Stay with me. Stay with me, Sammy. Keep talkin'."
The fourth man escaped the building just as Castiel and Claire came inside. The young girl gave a choked scream at the sight, while Cas' focus went straight to the brothers, disregarding the dead in the room. Claire hung back, eyes wide in terror, as Castiel approached the Winchesters. Dean looked up at the angel, blood covering his face and hands.
"Help him, Cas. You gotta help him," his voice shook as Sam's skin slowly grew paler.
"No, Dean," Sam's voice rasped softly, "No."
"What…what are you talking about, Sam?! You're hurt!" Dean ran his hand through his brother's hair, as he had done when he was a kid.
"Let me go," Sam sucked in a painful breath with a small whimper of pain, but then a small smirk grew on his face, "Can't cheat death forever."
"No, Sam!" Dean choked back tears, "Just this one time. You can't die because of me. I can't be the one who killed you. Cas, heal him!"
Castiel extended his hand to Sam's wound, but the younger Winchester grabbed his wrist weakly, "Please, Cas."
The angel looked from Sam to Dean, pain in his eyes. Castiel was torn. Sam had fought for so long, suffered through so much pain and torment. He deserved his long-awaited rest in heaven more than anyone he knew, besides Dean. But Dean needed him. Dean couldn't, or wouldn't, go on without his little brother by his side. His thoughts were interrupted by a quiet cry of pain from Sam as he removed his hands from the wound.
"Sammy," Dean shook his head helplessly, "Please."
Sam grabbed hold of his big brother's hand, wincing a little and looking up at him, "Thank you."
"For what?" Dean furiously wiped away tears with his free hand, before wrapping an arm around his brother in a hug.
"For being the best big brother I coulda wished for," the younger Winchester smiled, his skin almost grey, "Jerk."
Dean couldn't help but crack a small smile, "Bitch."
Sam chuckled softly, although the movement was visibly causing him pain. Dean clung to his hand, holding his brother close with the other. It wasn't too long after that.
"Sam?" he whispered, looking into Sam's lifeless eyes, "Sam?"
No response.
"He's gone, Dean," Cas reached and gently closed Sam's eyes. Maybe now he could rest in peace after all this time. Claire, from a distance, let out a sob.
Dean hugged the body of Sam Winchester for a long time, and Cas let him do so. He knew what was coming next, and he'd rather not face it just yet. Dean needed some time, and the angel didn't want to lose his other best friend.
"You know what to do," the lone Winchester's voice still shook as he laid Sam's body on the ground, allowing his brother's cold hand to slip out of his grip. His eyes were dull and lifeless. Uncaring. He couldn't go on now.
"Dean…" Cas tried to protest.
"Cas," the hunter waved the angel into silence dismissively.
"Claire," Castiel turned to his vessel's daughter with sad eyes, "Wait outside."
Without hesitation, the young girl nodded and disappeared out the door. Dean looked into Castiel's eyes one last time before closing his own. Waiting, just waiting, as Cas placed his hand on his forehead.