The ceiling was dirt.
That was his first fully coherent observation, catalogued with a clarity that felt new and slightly disorienting, the way a familiar room looks different after someone has replaced all the lightbulbs. His mind was processing everything — the texture of the tunnel floor beneath him, the smell of old stone and dark water, the specific quality of the silence that had settled after the cave-in — with a thoroughness that thirteen-year-old Ron Weasley's brain had never quite managed.
It felt like going from an old dial-up connection to something with actual bandwidth.
He was lying on his back. Gilderoy Lockhart was lying approximately four feet to his left, unconscious, his robes slightly askew and his famously handsome face wearing an expression of absolute vacancy that was, if anything, an improvement. The wand that had backfired on him was somewhere in the rubble.
The cave-in was behind him. In front of him, in the direction that mattered, was darkness and the faint sound of Harry's footsteps already retreating.
"Ron?" Harry's voice, tight with controlled worry, came back to him through the tunnel. "Are you alright?"
He sat up. Took one breath. Then another. His body felt — different. Corrected, the being had said, and he understood now what that meant. He'd been inhabiting a thirteen-year-old body for approximately six seconds and already he could feel the absence of things that should have been absent years ago — the low-grade tension in muscles that had been badly postured for too long, the specific kind of tiredness that came from years of not quite enough iron in the diet, the dozen small physical debts that Ron had been unknowingly carrying. They were gone. Not replaced by anything extraordinary. Just gone, leaving a body that felt properly, cleanly functional.
Baseline, the being had said.
He'd take it.
"I'm fine!" he called back. His voice came out steady, which he appreciated. "Go! Don't wait for me — keep moving, I'll try to make a path through!"
A beat of silence. He could almost feel Harry wanting to argue with this and overriding the impulse through sheer force of urgency.
"Be careful," Harry said, and then his footsteps resumed, faster now.
He waited until they faded.
Then he sat very still for thirty seconds and let himself think.
The eidetic memory was — a lot. That was the most honest assessment he could make. His own life was there in its entirety, organized and accessible the way well-shelved books are accessible — you knew where everything was, and you could retrieve it without hunting. Ron's life was the same. Thirteen years of a warm, crowded, occasionally maddening Weasley childhood, laid out with the same clarity. The twins' voices, his mum's cooking, his dad's absolute unhinged delight at anything remotely Muggle. Percy's pointed disapproval. Bill's postcards from Egypt. Charlie's enthusiastic letters about dragons that always seemed slightly singed around the edges.
He would need to be careful with all of this. He had Ron's memories but not Ron's instincts, and those weren't the same thing. Ron knew his family the way you know something you've lived inside. He would have to learn to know them, which looked identical from the outside but felt different from within.
He could work with that.
What he couldn't afford to do was sit here cataloguing memories while Harry Potter was alone in the Chamber of Secrets with a thousand-year-old basilisk.
He got to his feet — steadily, which he noted with something between relief and satisfaction — and turned to the cave-in.
It was substantial. The collapsed section stretched roughly three meters, a dense mess of stone and earth and what appeared to be bits of ancient piping, packed in a way that would have been entirely impassable for a thirteen-year-old with a broken wand and no particular physical advantages.
He pulled Ron's wand — his wand, now — from his robe and looked at it. Unicorn hair and willow, twelve inches. Functional, though not as responsive as something properly matched. He thought of the wand he'd need to get, hawthorn and thunderbird tail feather, and filed it away for later.
He began to work.
There was no magic. That was the first and most clarifying fact of the situation. Ron's wand — his wand, currently — was broken, had been broken since the Whomping Willow, held together by spellotape and optimism and neither of those things had survived the backfire. He could feel the pieces of it in his robe pocket, two clean halves of willow and a curl of unicorn hair that had been the core, and they were entirely useless to him.
So. No wand. A cave-in. A ticking clock.
He took off his outer robe, rolled up his sleeves, and got to work.
It was entirely physical — hands and leverage and the specific unglamorous problem-solving of someone who needed to move a significant quantity of rock without magic and without the kind of upper body development that arrived sometime after thirteen. He worked methodically, which helped. Ron's body had been corrected to its proper baseline and that baseline included the muscle memory of someone who had grown up on a working property, who had helped de-gnome gardens and haul firewood and assist with the kind of domestic magical upkeep that larger families managed through collective effort rather than spells. Not strong in any remarkable way. Strong enough.
He moved the smaller rocks first, clearing weight from above before tackling the larger pieces beneath. He tested each section before committing his weight to it. He thought about structural integrity in the specific way that someone who had never formally studied it could think about it — intuitively, carefully, informed by the basic principle that the goal was a gap large enough to squeeze through without bringing the rest of it down on top of him.
His hands were scraped and his arms ached dully by the time he found the gap, but the gap was there — low to the ground, perhaps sixty centimeters at its widest — and that was all it needed to be.
His mind ran alongside the physical work, quiet and quick, turning over the immediate situation with the kind of clean analytical focus he suspected was partly the Occlumency and partly simply what happened when a mind was allowed to work without the background noise of anxiety and self-doubt that had apparently been Ron's default operating state.
Harry was down there right now. Harry, who was twelve years old, facing a basilisk with a sword he'd pulled from a hat and a phoenix he hadn't called, supported by nothing except the particular brand of terrifying courage that Harry seemed to generate from some inexhaustible internal reserve. Harry, who in approximately the next few minutes was going to kill the basilisk and get himself fatally poisoned in the process, and then get saved by Fawkes' tears, and the whole sequence would end with Tom Riddle diminished to nothing and Ginny waking on the Chamber floor.
He knew all of this. He also knew that knowing how a thing ended did not mean he could stand here calmly doing nothing while it unfolded.
He worked faster.
The gap, when it came, was not large — perhaps sixty centimeters at its widest, low to the ground, the kind of space that required an undignified scramble — but it was enough. He pushed through on his stomach, felt stone scrape at his back, and emerged on the other side in a graceless heap that he immediately converted into forward motion because stopping to feel embarrassed about it would have been a poor use of time.
He ran.