Sam is leaving. Dean kept repeating that thought in his head. The thought was simple enough, but every time he repeated it, he felt the same agonizing jolt of pain. Sam is leaving.
Dean had been shocked into silence when Sam revealed his plan. There were no tears, no words. He found himself staring blankly at his brother. Leaving. For college. Leaving. Without me. Me. And Sam had looked steadily at Dean, eyes pleading. But Dean couldn't give Sam the comfort he was obviously seeking. Anger began to burn through him. How can he do this? Why would he want to leave us? To leave me?
And then John had started yelling. Sam gave back as good as he got. Both men bristling, years of building resentment unleashed in a single explosive moment. And for the first time, John and Sam were fighting and Dean didn't want to jump in to defend Sam. All these years he had bit his tongue when what he wanted to do was protect his little brother from their father. But he never stood up to John, as much as it hurt. Because he didn't want to be forced to leave Sam. Didn't Sam know that Dean would rather die than leave him? After all of that, Sam was choosing to leave Dean. The thought was ripping Dean's heart to pieces. He almost wanted to yell at Sam himself.
How could you do this to me?
Sam was moving towards the door.
"If you walk out that door, you never come back!" John bellowed.
Sam put his hand on the door handle. He turned to look at Dean, but his brother refused to return his gaze. He refused to look at Sam, to see the pain in his eyes. Because maybe he would start to feel bad for Sam. He might start to feel that familiar urge to comfort and protect his brother. As if Sam wasn't choosing to leave them. To leave him. As if Sam wasn't running away from his family.
Sam opened the door and walked out without another word. John stormed into the bathroom and slammed the door. Dean sank onto the bed, blinking hard. Sam is leaving.