Maybe the place didn't have quite as many floors as Harry had assumed from the building's height: it seemed Ekrizdis was similar to the founders of Hogwarts in his love of headroom. A troll that was basically two adults tall had been able to comfortably fit into the school's hallways and bathrooms their first year, and even it would have felt like there was a lot of wasted space in Azkaban's layout. The hallway they entered through was probably ten yards high, and wide enough to drive a lorry through without worrying about hitting walls. The entire place was somehow getting enough light from the morning outside that they could even make out the upper reaches of the area.
"Yeah, it's a lot," Dawlish answered Harry's unasked question, watching the boy boggle at the high ceilings. "At least they can have the dementors float along the top so nobody working here is in danger of bumping into one of them."
"You must have to stay right next to the fires to keep warm," Harry complained, noticing that there were, indeed, braziers set up all the way along the walls of the hallway every couple of yards.
"Guard posts are in rooms that are a little less…" Dawlish struggled for the word.
"Cyclopean," Dumbledore supplied, absently.
"That, yeah… so it's not as bad in those places. But, yeah, you're not wrong," the auror finished.
They'd been dropped off on the pier and let through a small, heavily-fortified guard post at the water line by a couple of other aurors. Under the auspices of the Chief Warlock and a senior auror, they were allowed to keep their wands and wander on their own recognizance, but were cautioned very heavily not to give anything to the prisoners or risk a close encounter with the dementors. They'd climbed a spiral staircase up a long ways before hitting the presumed main level. There could obviously be hidden levels of the complex between the water line and where they were now. Harry's map was basically just a very vague wireframe of the tower, with the actual passages filling in as he walked through them.
There was still an immense amount of map to fill in.
"This cuts into the courtyard," Dawish continued explaining as they walked, gesturing at the end of the hallway, about 60 yards from where they'd entered. They had seemingly come in at one of the tower's corners; Harry could see from the map that the distance to the courtyard would be around half that if they'd just cut across one of the sides. But Ekrizdis had probably wanted an impressive hallway for the first approach. "There are stairs between levels, but the prison's mostly up top and it's a climb. Out in the courtyard, they installed lifts."
The entry hallways also didn't have doors on the floor level, only wall, but had them spaced along the ceiling every few yards. Harry's vague knowledge of castle siege tactics made him suspect they were basically firing positions for defenders against others invading the tower. "Has anyone been up there?" he asked.
"Yeah. Just cuts up to rooms on the next level," Dawlish answered. "We think they were put in to make it easier for the dementors to get around." Surely Ekrizdis wouldn't have installed habitrails for flying dementors when he'd first made the place, if they'd been a later accident?
"I think I need to see basically everything," Harry apologized, "so we may be climbing a lot of stairs?"
"It's forty-six floors!" Dawlish objected.
"Is that number important?" Harry wondered.
"It's twice twenty-three," Remus shrugged. To everyone's confusion, he whimsically added, "Fnord!"
"Forty-nine would be seven sevens," Dumbledore mused.
"So maybe three basement levels?" Harry figured, trying to locate a way down on his map. It hadn't appeared yet.
"What if we took the lift up and then the stairs down?" Remus suggested.
"Certainly easier on old knees," Dawlish allowed.
Harry nodded his agreement. He'd expect to find everything important lower in the building, so he wasn't sure going all the way to the top and down would be very efficient. But he did want to fill in the map.
The courtyard of the tower was not exactly the kind of exciting enclosed space one might expect from the term. With the height of the surrounding tower, all being open to the sky meant was that it was able to get rained into. There might be sunlight for a short period in times of the year when the noon sun happened to be directly overhead. At least there was some fresh air, with the drizzle. Inside, the corners of the triangle were maybe a hundred yards apart, and the ground was the natural rock of the island. As a testament to the power of the dementors and probably the rest of the dark magic suffusing the place, there weren't even hardy island plants in any of the crevices.
There were a few other features in the mostly-empty shadowed space. Large cisterns allowed for the collection of rainwater. A pair of magical lifts designed as basically counterweights (one would go down while the other went up) hugged one wall. And there was even a currently-empty "yard" of mostly-level terrain surrounded by fencing. Dawlish explained, "The lowest-security inmates get some time outside. It's more for being further from the dementors than seeing the sky."
The auror placed his wand against a pedestal between the lifts, and the closer one began to sink toward them as the higher started to rise. Even though both were empty, they seemed to reset to somewhere in the middle, perhaps to make it harder for escapees to immediately exit onto a lift at the top floors. They really weren't much more than large slabs of painted metal of the kind that catwalks were made of: grids of steel that were more empty space than platform. Presumably there was no good in having an exterior lift where water could puddle. Even with a tin roof and waist-high guardrails, they were still damp and had rust visible where the paint had chipped.
There was space enough for all four of them, just a simple latched gate as the entrance that Dawlish opened and then closed behind them. It was a good thing that Harry was used to heights from playing quidditch, because as the lift started to rise he realized there wasn't anything between him and the increasingly-distant ground other than some holey, rusted metal. Remus shuffled back toward the wall of the tower as they reached the halfway mark and passed the descending sister lift, his stomach rebelling a bit at being over a hundred yards in the air and still rising.
"I think, patronuses," Dumbledore cautioned, noticing that there were dementors swirling in the air above them.
Harry nodded, having been so busy watching the ground he'd forgotten the bigger danger. "Expecto patronum." A large chunk of his magical stamina bar immediately disappeared as he summoned his silvery canine, and his stamina regeneration rate was all but zero as he maintained it. It had started out even worse, before he got a mastery level in the spell, reducing the cost. He probably wouldn't have had enough resources to summon it at the beginning of the year. Everyone immediately felt better as the guardian imago began to patrol the borders of the lift, especially once the headmaster's silver phoenix joined it. A dementor that had been drifting closer out of curiosity backed off. None of the dark magic creatures had shown up on the minimap, limiting Harry to tracking them visually. At least they weren't glitching out his interface while they kept their distance.
The platform finally stopped with a slight jolt when it was level with the roofline. Harry could see that the roof was slightly canted to allow rain to run off either side. There were no crenelations for defenders, but long trenches in the center of the roof seemed like they could be used as concealed points to hold off attackers on brooms. And who knew whether there were defenses that could be transfigured in case of an actual attack? "We can go in through the trenches," Dawlish instructed, opening the other gate at the back of the lift and striding over the one foot gap between the platform and the roof. "Watch your step."
"Does it only go to the top?" Harry asked, glad that the platform at least didn't sway as he was momentarily leaping over a fall that was far enough that he could almost reach terminal velocity. He managed to maintain his footing on the perpetually-water-slick roof.
"Couple of other doors that we passed," the auror shrugged. "They're annoying to get open, though."
The recessed trenches had adequate drainage into gutters at either side, and stone stairs led from them down into the tower. An arch exited off to either side before descending into the main level, and once again Harry spotted the "dementor tunnels" along the top of the hallway that were probably originally meant to be firing emplacements for defenders against anyone that made it down into the tower. While convenient to serve as passageways for the place's spectral guardians, he couldn't believe that was the intention.
"This is maximum security," Dawlish explained as they left the stairs. The floor was once again a wide hallway with the emplacements/dementor tunnels above, but instead of bare stone there were doors along the wall. In this section of hallway, they were open and clearly full of supplies: spare bedding, tins of food, and fuel for fires. But to either end, secure doorways stood, barred from their side. "Mostly Death Eaters, these days."
"Can the dementors cut into there through the ceiling?" Harry asked. His map was slowly filling in for this level, though beyond the doors there were only dots extending to the range he could usually sense people. They were spaced regularly, as if one to a room. Zooming in on the inmate dots, he found several names that didn't mean anything to him, though "Lestrange" seemed to be popular surname. He still mentally noted them for later, just in case (he wasn't sure in case of what).
"Yeah," Dawlish nodded.
"What if someone got smuggled a shrunken broom or something?" Harry figured. "They could fly up to the ceiling, then right out off the top."
"It's been tried," the auror agreed. "We scan for that kind of thing. But there are also wards at the top level. Anything other than a dementor tries to fly away from the tower, they get blown right back in and sucked into the courtyard."
"Huh, that would do it," Harry said, still looking at both the physical space and his map. It really was imposing.
Whisper to Sirius Black: We're up at your old level. How'd you even get out anyway?
They'd discovered the whisper function a few weeks earlier, when Harry had been trying to get Seamus to pipe down in potions class before losing them a ton of points. The intention to whisper had been translated into a direct message from the game system, identical to hearing Harry messaging the guild (at least according to the other Marauders he'd subsequently tried it with). Seamus seemed a little suspicious. Overall, it was a really confusing term for a private message using the game, but useful. Hermione's best guess was that it might make sense in a video game if you were trying to speak to someone privately to "whisper," but why that could be achieved at any distance was another confusing artifact of Harry's bizarre powers.
Sirius Black replies: It's intense, right? I slipped out while a dementor was opening my cell to feed me. They didn't even notice me as Padfoot.
Reply to Sirius Black: But the main door? And the roof? And the lift? And getting out the front?
Sirius Black replies: All timing, sneakiness, and luck. It's dark in there at night. If you're quiet enough, being a black dog in the dark is as good as invisible to slip through doors behind people. And I got on the lift going down while someone was coming up.
Reply to Sirius Black: Can I tell Dawlish that to sound smart? Without mentioning Padfoot, of course.
Sirius Black replies: Sure. I'm never going back there. Never.
"What if someone figured out some way to become invisible to dementors?" Harry acted like he was musing as the group had drifted toward one of the dividing doors. "Could they just kind of slip out when they were getting fed, and then maybe hide in corners in the dark to wait for doors to open?"
The old auror didn't shoot the idea down out of hand. He cocked his head and thought about it, eventually admitting, "I'm sure the wizards downstairs would tell you they'd never let someone just walk behind them like in one of those old cartoons…" It was interesting to Harry that Dawlish knew enough about muggles to reference that. "...but, yeah. In the dark, if someone was tired and just using their patronus light to get around… yeah. I'll talk to some people about better protocols. Do you need to see the Death Eaters, or can we head down?"
Harry glanced at the headmaster, who shook his head. "I would caution against it. Who knows what plots would start to percolate through those minds should they see young Harry. If the key to our investigations lies in their cells, then we shall have to. But I'd prefer to examine anything else first."
"Best thing I've heard since we got here," the auror agreed. "Just forty-five more levels to see, then. Going down?"