‘We’ve got to get to the lift,’ he said as he hurried through the next room.

‘They’ll shoot us before we reach it,’ Nina replied. ‘But I saw a plan of the bunker when I arrived – there’s another way out!’ They ran on through the underground maze.

‘Shut the door!’ Eleanor cried as Broates pushed her out of the chamber at a run. ‘Switch on the extractors, vent the gas!’

The butler hurried to the control panel – only to look up in alarm. ‘It’s not working!’

She saw the bullet holes in the console. ‘You idiots!’ she shouted at her men, before glaring at the side exit. ‘They must be trying to reach the emergency stairwell. Get after them! Now!’

Wintz and the last guard raced in pursuit. Harhund and Miller, though, headed for the main corridor. ‘Where are you going?’ she demanded.

‘Are you kidding, Mother?’ Miller said, jabbing a finger back at the roiling poison. ‘I’m getting away from that!’

‘I suggest you do too,’ Harhund added as they exited.

Broates hurried to Eleanor. ‘Mrs Miller, I can’t stop the gas from spreading. You must get out of here. Quickly!’ He pushed her after the two men.

Miller and Harhund charged through the bunker to the elevator. Behind them, more alarms sounded: the toxin was spreading through the ventilation system to other rooms. ‘Come on, come on,’ Miller gasped as he stabbed at the call button. ‘Come on! We were the last people to use it, why the fuck isn’t it—’ The doors slid open. He rushed inside, Harhund joining him.

‘Donny! Wait!’ They looked back to see Eleanor, Broates propelling her at a straining run. ‘Hold the door!’

Miller reached out to stop it from closing – then caught Harhund’s eye. A pause, mixed emotions crossing his face . . . and he stepped back.

Eleanor’s own expression was one of disbelief. ‘What are you doing? Donny! Hold the door!’

He said nothing, remaining motionless – until the doors started to close again. He held up his hands in a shrug as if there was nothing he could do as metal slammed shut between them.

She stared at the elevator, speechless, before exploding in anger. ‘You little shit!’

Broates quickly turned her around. ‘I’ll get you to the emergency stairs.’ He pushed the furious old woman back down the corridor.

‘This map you saw,’ Eddie said to Nina as they ran pell-mell through the concrete warren. ‘Don’t suppose you remember any details from it? ’Cause I think we’re lost!’

‘The other exit was at the opposite end to the elevator,’ she told him. ‘If we keep going this way, we should reach it. Eventually.’

‘Be just our luck if it’s at the end of a five-mile tunnel!’ They reached a T-junction. ‘Okay, which way?’

Nina looked in both directions, seeing numerous doors, but neither option appeared preferable. ‘Uh . . . left?’