The "thunk" of the amulet as it hit the bottom of the can cut right through Sam like no sound he could remember. It had a finality to it that Sam simply couldn't accept. His feet were in motion before he even thought about it and he scooped the necklace out of the garbage like a kid trying to save a piece of candy using the "five second rule".
"Sam." Through the open doorway Sam could see that Dean had paused on the sidewalk halfway to the Impala. His shoulders were rigid and the cords on the back of his neck stood out prominently. Dean's face was turned slightly to the right; not far enough to look back, but tuned in to listen.
"Leave it, Sam." Dean's voice had a growl to it that was straight out of the John Winchester playbook. It was a tone that said, "Don't you dare make me repeat myself or there will be hell to pay." Once upon a time Sam was hardwired to respond to an order given in that voice, but those days were long gone.
Unconsciously Sam wound the black cord around the fingers of his right hand and closed his fingers around the ancient amulet. Again he moved forward without volition, pursuing Dean out of the room; maybe he was hoping to find the right words between the door and the car, but he never had a chance.
Dean tossed his duffle and turned to his left in one smooth motion. Sam's open handed gesture was met with a fist to his face; he should've known better than to leave his head unprotected. Sam stumbled back into the door jam and instinctively fell into a defensive position. Even under attack Sam understood that it wasn't really him that Dean was fighting, but after everything that had happened it was hard not to take it personally.
It worked to Sam's advantage at first that Dean was so angry, so desperate to make contact that he was wild and uncontrolled. If Dean had been precise in his blows Sam would've had to fight back instead of just defending himself, and the last thing Sam wanted or needed to do at the moment was to hurt Dean. But Dean's fierce rage didn't exhaust itself in a flurry of fists like Sam anticipated, instead it became white-hot and focused; that's when Sam knew he was in trouble.
Dropping his defensive stance, Sam took the offensive – not to defeat, but to contain. Ducking below Dean's right swing, Sam skirted behind him while tangling up his right arm. Sam thrust his right leg between Dean's legs and hooked Dean's left ankle, trapping it between Sam's feet. Using the car for support, Sam leaned back pulling Dean far enough off his feet to take away his leverage, but Dean wasn't going to go down without a fight.
Dean used his left arm to elbow Sam in the ribs. Sam's natural reaction was to curl up, and when Dean had both feet back on the ground he pulled away as hard as he could. However he didn't manage to escape Sam's grip; Dean only achieved a roll to the right landing him against the driver's side door where Sam used his height and weight to pin him to the car.
Sam breathed heavily against Dean, not knowing what the hell to do next. Dean was trembling beneath Sam, but he didn't know if it was with repressed rage or a desperate attempt to keep himself from flying apart. The amulet that Sam had wrapped around his fingers was trapped between his hand and Dean's arm. He could feel it biting into his skin, marking them both.
Dean's trembling increased and he gasped out in a voice that was rough with despair, ringing with defiance and all his, "I don't need it, Sam."
Sam stepped closer and leaned his forehead against the back of Dean's head. "But I do."
The tension in Dean's frame increased for a fraction of a second and neither one of them breathed. Sam could almost feel Dean working out what Sam had said, processing Sam's point of view in a way he was unable to in heaven. Dean breathed out and his body relaxed. Though Sam still held his arm, Dean used his hand to tap the roof of the car - tap, tap - a signal that the spar had ended and the pinned brother ceded victory to the other.
Sam responded automatically stepping back, releasing Dean's arm and untangling their legs. With his back still to Sam, Dean ran his right hand over his face. "Do what you want, Sam." The accompanying laugh was bitter, implying that's just what Sam would do anyway. So much for Dean understanding Sam's point of view.
It wasn't how Sam wanted to win. He leaned back against the car in silence. Dean ignored him as he moved around the car and opened the trunk, throwing up a visual barrier between them.
Sam looked down at the necklace in his hand. It was bloody from the fight having bitten both of them. He rubbed his thumb restlessly over the tiny, golden figure. It wasn't where it belonged yet, but Sam had to believe it would it would get back there eventually. It had to for both of their sakes.