The entire concourse shook as they emerged, the air now so thick and fluid it almost felt like being underwater. That dreadful ululation seemed to vibrate right through the atoms in Saul’s body. He looked up at the twists of light that now crowded the concourse ceiling. Something about them made his eyes hurt, so that he couldn’t look at them for more than a second or two.

‘Thirty minutes won’t be enough time, will it?’ Amy yelled to him over the din. ‘Whatever’s driving those clouds is going to get through before that. No telling what might happen then.’

Saul remembered something. ‘The HMX,’ he shouted.

‘The what?’

‘Explosives,’ Saul yelled. ‘Those troopers Mitchell killed had an APC filled with HMX explosives. They were wiring the Florida gate so they could blow it up.’

‘Would that work?’

He shook his head. ‘I don’t know. Maybe it might delay the clouds, but that’s about it.’

‘Better than nothing,’ she yelled back.

He nodded, and they made their way quickly over to the APC. Saul took the lead, but Amy struggled to keep up, so he put one arm around her waist and half carried her. She didn’t protest or try to push him away, which only showed how exhausted she was. In truth, he was running on little more than adrenalin himself.

All they had to do was keep going just a little longer.

‘I’m getting a bit too old for this,’ panted Amy. ‘Seriously.’

They now came to the barricades, where the bodies of Merrill and Dallas still lay alongside a crate filled with bricks of HMX. Amy picked one up and studied it for a moment.

‘Demolition charges,’ she said, glancing towards him, then slumped against one of the barricades, looking pale and ill. ‘By the looks of it, the detonators are already in place.’

‘I didn’t know you were some kind of demolitions expert?’

‘We used HMX when we were building biomes out on Newton. Good for excavating land real fast.’

Something about the ululation made Saul’s skin itch like it was burning. ‘The question is, how were they going to set off the detonation?’

‘Remote trigger?’ she replied. ‘That’s my guess, anyway.’

‘You mean through their contacts?’

‘No.’ She shook her head. ‘That way there’s too big a risk that somebody might hack your contacts and then trigger an explosion from a long way off. They’d have planned to use a dedicated device of some sort.’ She nodded towards Merrill’s butchered corpse. ‘Check him out. Maybe he’s got something on him.’

Saul grimaced as he bent over Merrill’s body, pushing his hand inside pockets soaked with the dead man’s blood. When he found nothing, he moved over to Dallas, and soon found a slim device sporting several inlaid buttons.