She didn’t know whether to laugh or cry, and ended up doing a messy combination of both as she ran to the boot and began to stack her kit on the pavement. Unable to carry everything, she ransacked her bags, amalgamating them into one and throwing vials of drugs into her pockets. A girl approached Jem as she was settling the response bag and defib on her shoulders.

“Tahlia?”

The girl nodded, squinting against the blues Jem had left on to guide others in. She was filthy and gaunt, and her clothes were wet through. Her hair, almost hidden by her cap, looked as if it had been hacked off with a penknife. “Rosie’s been talking to me,” she said. “But the water’s getting deeper.”

“Bloody hell.” Jem tapped her pocket, checking for her inhaler. “Come on, let’s go.”

They weaved across the wasteland at a near jog, taking a route Tahlia was obviously familiar with, despite the fresh hazards of near-darkness and unpredictable flotsam. Using a stack of rickety crates like a staircase, she scrambled through a broken ground-floor window.

“Hurry.” She beckoned to Jem, heedless of Jem’s burden or the rattle of her breathing.

Jem ignored them as well, launching herself over the sill and keeping up with Tahlia. From a distance, she saw the gaping hole in the floor, the splintered wood splattered with streaks of paint that hadn’t been enough to alert Rosie.

“Is she down there?” Jem knelt at the edge, straining to catch sight of anything but whirls of brown water in her torchlight.

“She’s this way,” Tahlia said, hauling on Jem’s sleeve. “She got pulled farther along.” Choosing her path with care, she guided Jem to a smaller opening seemingly designed for people rather than goods or waste, with a concrete lining and a metal access ladder. “Do I have to go down?” she asked, crouching at the top.

“No.” Jem took off her high-vis jacket and wrapped it around Tahlia’s shoulders. “You stay close by and yell as soon as you hear people coming. Show them where we are.”

“What if it’s not them?” Tahlia said. She was rocking gently, back and forth. “Men keep coming to find me.”

Jem set a foot on the ladder and swung into the gap. “Look for the uniforms. Yellow jackets like mine, helmets, big boots. There’ll be loads of them, and they won’t be quiet.”

Tahlia studied the fluorescent material of Jem’s jacket. “The other men all wear black.”

“You won’t be able to miss this bunch, I promise,” Jem said, already on the move. “They won’t be long. Just be brave.”