The vehicle trundled a foot or so forward, and then the engine whined as the slack was taken up on the cable. My heart thudded at the sight of the fiery tide spreading towards me. How long before the lava reached the EV? One minute? Or less?

‘Floor it,’ Nadia yelled. ‘She’s moving, but she’s still not out of that hole.’

‘If I floor it,’ I said through gritted teeth, ‘I’ll drive straight into the fucking lava.’

‘No, you won’t,’ Nadia yelled, with what struck me as a remarkable lack of conviction.

I floored it and felt the rumble of the engine through the soles of my boots. The EV trembled around me and then, suddenly, slipped forward a couple of inches.

‘That’s it, Jerry!’ Nadia yelled, sounding as if she was on the verge of hysteria. ‘She’s moving! Keep at it!’

I half-stood in the driver’s seat, staring with clenched teeth through the windscreen at the lava. It was right in front of the EV now, and getting closer . . .

. . . Closer . . .

The EV surged forwards, and into the lava. Flames shot up around the windscreen as the tyres were instantly burned to a crisp.

Nadia was yelling something, but I wasn’t paying attention. The floor shuddered beneath me, and the whole EV listed to one side. Flames were rushing up the front of the vehicle, and I saw the glass of the windscreen blacken and crack as I ran to the rear, where the airlock door was mounted.

I tried to open it, but it was stuck.

‘Jesus Christ!’ I screamed. ‘I’m stuck in here! Nadia, get me out!’

‘I’m trying!’ she yelled back. ‘Goddam son of a bitch . . .’

The airlock opened suddenly, and I fell out and on the ground. I looked around and saw a wall of lava come rolling towards me, barely metres away.

A pair of gloved hands grabbed hold of me and I stumbled to my feet. ‘Run, you idiot!’ she screamed. ‘Just fucking run!’

I ran. We both did, regardless of how hard it was in the suits we wore. I glanced back in time to see the EV sinking into the lava, surrounded by great gouts of flame that rose towards the vault ceiling. When I heard – no, felt – the ground shudder beneath my feet with extraordinary violence, I at first thought something on board the EV had exploded.

Except that didn’t make sense, I realized, as we ran towards the forest of girders between us and the next vault. There was nothing inside the EV that could possibly have triggered a ground shock of that nature.

I made the mistake of looking over my shoulder a second time as we made our way through the maze of girders blocking the tunnel. One entire wall of the first vault had come crumbling down, a veritable ocean of white-hot magma spilling through the rent and swamping almost the entire vault in seconds.