Karl let out a breath, and that was when he realised that he’d been holding it. His chest was heaving as if he’d been running. He heard Liz’s ragged breathing a couple of feet away. Saw the shape of her chest rising and falling. Same story. Nervous energy oozing out of both of them.

She stumbled. His anxiety exploded, and he grabbed her, fearful that the noise would bring the gunman pounding down upon them.

‘I’m okay,’ she said. She struggled out of his grasp, and her black shape bent and sat on one of the rails. He didn’t want to stop, was desperate to get out of here and back to Katie, but he sat opposite her, facing her. He knew the gunman was far behind.

‘Let’s hope a train doesn’t come,’ she said, repeating her joke from earlier.

‘We could do with the light.’

‘Nah, you don’t want to see my face. Make-up all messy.’

‘I think with all this dirt around we probably look like coal miners by now.’

They sat for a few moments. Back down the tunnel, the darkness seemed to pulse and shift. He stared until he was sure the kaleidoscopic swirl didn’t camouflage a man crawling towards them.

‘What was that thing with the smoke, that grenade thing you threw?’

She was rubbing her hands across her face, trying to remove the grime. His coal miner joke must have set that off.

‘The grenade that let off all the smoke? Smoke grenade.’

She laughed. ‘Very funny. Where did you get that?’

‘Internet. Two hundred quid, up in smoke.’

‘Who’d need one of those for personal defence?’

He said: ‘People on the run, apparently.’

She laughed. ‘I’m guessing that stuff’s not legal to sell.’

She was just killing time, talking to make the minutes fly by. Time was not something he could spare, though. He stood. ‘No. That’s why I had it upstairs.’

He watched her straighten her dress and could tell she was thinking of something else to say. He looked at the way ahead. How far until the station? A mile, or was it thirty feet away? He wanted to get moving.

What she decided upon was: ‘How did you meet your wife?’

He sighed. ‘Let’s go. We can’t waste time.’

They started walking again. After a minute, he answered her question.

‘Like you. Childhood sweethearts. She was the neighbour’s kid. We were the only children on that street. Just friends until she was thirteen, and I was twelve. She wanted to practise kissing, and there was no one else around.’

‘So you having a loving wife and a baby on the way. I guess you feel you’re a lucky man.’

‘I never won the lottery, but never got stabbed to death in a piss-stained alleyway, either. I’m happy with the middle ground.’

More silence. Thirty seconds in, she stumbled over something and he turned, caught her as she crashed into him. In his arms, she said: ‘What’s your plan?’

He made sure she was balanced, then turned and started walking again. ‘Get to a phone. Tell the damn police what happened. And tell my wife she’s got to run from our family home because of all this shit.’ His anxiety was rising again.

After another minute or so of silence, she said: ‘It’s morning now. They shouldn’t still be after us. Something’s wrong. We need to find my husband.’

‘I’m going home. You do what you want.’ He could feel his anger welling up.

‘He might still be tied up at the cottage. Maybe they tied everyone up. We have to go there and release him. Then he can get to work sorting out this problem. You have to take me there.’

Knowing he was so irritated that he would only say something she wouldn’t like, he refused to respond. Was the gunman approaching his house right now? Closing in on his wife and child?

‘Ron can fix all this. He’ll know what to do. But he’ll be worried about me. We’ll find a taxi and get straight there. They won’t still be there, not if they’re out chasing us.’

He wanted to believe that Katie would be safe. The gunman and his cronies hadn’t gone to the house this morning, had they? They’d chosen the shop. The hunt was for Karl and Liz, after all. Hopefully Katie would be ignored. Safe. Hopefully, when he hadn’t called her, she had packed a bag and got out of there.

‘Are you listening? I need to get to my husband.’

‘Fuck him,’ Karl snapped.

‘No, fuck you.’

He heard her stop, but he continued walking. Faster now, with bigger steps. If she wanted to stay down here, so be it. But he was going.

He stopped, and turned.

‘I’m sorry.’

It hit him then. He had a duty to protect his wife and unborn child any way he could, but that didn’t mean he could abandon this woman. The men who had tried to break into his house had failed, hadn’t they? Because Katie had slept soundly all night in a warm bed. But they hadn’t failed at Liz’s house, had they? Because Liz had fled through the woods, pursued by a masked man, and this morning she was lost underground and still had no idea what had happened to the man she loved. He hadn’t wanted any of this trouble, but he was in the thick of it now and had a responsibility to help. Anything less would be wrong. If Katie had been lost down here with another man and that guy had refused to help…

But there was something else. Something he hadn’t wanted to think about, but now, knowing Katie might be in danger, knowing that their pursuers were not going to give up, it was pushing to the front of his mind.

‘I’m sorry. Look, we’ll sort this out. We’ll call the police and send them to our houses, and we’ll get there and make sure everyone’s safe. But let’s get out of this tunnel first, okay?’

‘I don’t think you should assume the police will make everything okay.’

Her sentence highlighted exactly what he couldn’t stop thinking about. Maybe the cops wouldn’t be able to do much. They might fail to get the names of everyone involved, or miss a vital gang member when they took everyone down. All it would take was one bad guy left on the streets with a working pair of legs and Karl’s address. Maybe the only person who could totally fix this problem was this woman’s husband. Street justice wasn’t exactly what Karl wanted, but if it meant an end to the threat against Katie and Michael… And it wouldn’t be his fault, would it? All he’d done was save someone’s life. What Liz did with her continued existence would not be on his head.

He stopped and waited for her, and, side by side, they stumbled on into the void.