"Sam," the Doctor called out, taking a few running steps to catch up to Sam when the younger Winchester didn't stop or even turn to acknowledge him.

"Doctor," Sam said coolly. And that was interesting again. Now that Dean wasn't around to see them, Sam had dropped even the bare pretenses he'd put up before. He wasn't trying to pretend things were normal. He wasn't downplaying the blank space in his mind.

The Doctor came to a stop, and this time, Sam stopped with him. "When did you notice something had gone wrong?" he asked, not giving Sam the option to pretend it was okay.

Sam raised both eyebrows and crossed his arms. "What do you care anyway? You weren't around when the world nearly ended; what does the aftermath matter to you?"

The Doctor narrowed his eyes. "You weren't there for many times the world nearly ended, Sam," he said, his tone cooler than usual. But no one was there. No one who cared. And the Doctor, for as much as he loved the Winchesters, was not a jolly jester the boys could push around and blame for their problems. "I'll defend this world at every turn, but I won't fight every battle."

Sam glared to match the Doctor and then scoffed, turning on his heel. "Typical."

The Doctor walked around Sam to get in his path, his index finger out to poke him in the center of the chest. "You have to know there's nothing up there," he said, flicking his finger up to point at Sam's head. "You have to know it."

"Yeah? And what do you expect me to do about it, huh?" Sam asked. "Or did it occur to you that this is better?"

"What are you talking about?"

Sam knocked the Doctor's head away from him. "Every slipup we made leading up to that mess was because we were scared."

"Concerned for each other," the Doctor said, but Sam waved him off.

"Scared."

"And you're not scared anymore," the Doctor guessed, frowning as he watched the way Sam's jaw tightened at the corner. He wasn't afraid, and he didn't care, but he was capable of violence. And that was dangerous.

"No."

"And you don't care anymore."

Sam paused just long enough that the Doctor knew he knew the correct answer to the question. But again, it was just the two of them. And so, he answered truthfully: "No."

"I see."

Sam narrowed his eyes again, nearly to slits. "What's your point, Doctor?" he asked, a threat laced in his words that the Doctor hated hearing directed toward him, though it wasn't a new feeling, either. He knew that, no matter how much he and the Winchesters both spoke highly of each other, their relationship had always been tenuous. He wasn't human, and they were hunters.

But this time, the threat didn't have any of the usual hesitation, any of the acknowledgement of their history.

"I can try to fix it."

"Don't." Sam pointed at the Doctor, the threat further accentuated by the glare behind his eyes. "Whatever it was, I don't want it back." A smile twisted its way across his features. "Do you have any idea how much I used to hold back?"

The Doctor ignored the smile and took a step toward Sam, holding his gaze. "I get that, actually," he said. "Do you have any idea how much I hold back?" he added, letting his voice drop as well.

Sam stood up straighter, visibly reevaluating the Doctor, both eyebrows raised as he looked him over. And then, he relaxed his stance entirely and let out a scoff of a laugh. "Nice, Doc."

"I was serious."

"Yeah, I noticed."

The Doctor watched Sam, frowning, but before he could say anything else, he heard footsteps approaching and saw Dean and the young woman they had rescued making their way toward the two of them. And so, the Doctor pointed at Sam in a warning. "Talk to your brother about this. You can't think he doesn't know something's going on."

"I don't know what I'd tell him," Sam pointed out. "You don't know what happened either."

"I can look into it."

"Sure, Doc. And when we see you in a couple years, I'm sure that'll be real helpful."

The Doctor felt the corner of his jaw tighten—because that was actually a good jab. He was precise now when he brought Clara to and from her home, but the boys hadn't always known him to be. "Well, Sam, this has been enlightening," he said, his tone brighter again as Dean and the girl approached.

"Always is," Sam said, also slipping into something a little more approachable as Dean joined them.

And that was interesting, too. Even though Sam said he didn't care anymore, he was making an actual effort to shield Dean from the worst of whatever had left him that empty. It was like part of him remembered how important Dean was to him, and in service of that memory of care, he was willing to change his behavior just enough that it could count as affection, if looked at sideways.

But then, that was the Winchesters. Not much could get between them.

"You two out here gossiping about me?" Dean asked with a crooked grin that made the girl he was looking after smile too—which, of course, had him grinning even wider.

Again, some things never changed. And the Doctor was almost tempted to tell him to stop it, just to see what that felt like in this body and to see how Dean would react.

But instead, he waved Dean over. "How are you feeling?" he asked the girl with him.

"Much better, thank you," the girl said. She was smiling, but she was obviously hurting as well. Best that the Doctor get out of the way so the Winchesters could get her to help. He could check in with them without listening ears.

"So, I guess this is where we part ways," Sam said pointedly.

Ah, so that was how he wanted to play this. The Doctor gave him a pointed look, but Dean was flirting and missed it. "I can stay," he said, but Sam was already shaking his head.

"We've got places to be."

"Yeah, gotta get out of here before someone decides this was all our fault. Again," Dean said.

"We'll see you next time the TARDIS wants to say hello," Sam said.

"Tell her I'll miss her," Dean added, his grin warmer.

The Doctor frowned between them, but before he could think of something to say, the two of them fell into step with each other, seamlessly moving as one, almost as if nothing had changed.

Almost.