‘Get on board!’ I heard Rozalia yell. ‘Nadia, are you there, sweetheart?’

The second EV was out of its hole, and waiting ready to carry us away. The others had had the same thought, depressurizing the interior of their EV so they didn’t need to waste too much time cycling everyone through one at a time. Gloved hands reached down and hauled us up and inside as the airlock door swung open, and by the time I was fully inside the vehicle it was already moving at a fair clip.

‘What just happened back there?’ a voice asked from up front. I looked over at the driver, a thin, dark-skinned woman, her helmet propped up on the dashboard before her, and recognized her voice as Rozalia’s. ‘That’s the biggest tremor yet.’

‘Just drive,’ gasped Nadia. ‘As fast as you can, and don’t stop.’

I heard a hiss as the vehicle repressurized, the sound growing louder at first before quickly fading away. I pulled my helmet off, and the rest followed suit. The two Authority scientists, a man and woman, sat close together on the floor of the EV, clearly frightened out of their wits.

The EV bounced over the uneven floor of the vault with such force that I had to steady myself against one side. Nadia had made her way up front to take a seat next to Rozalia, who stared fixedly ahead as she steered. Nadia murmured something to her that I couldn’t make out, then reached over to touch the other woman’s hair in a way that implied a great deal of intimacy.

I got a look at the rear-view monitor on the dashboard and saw a veritable ocean of white-hot lava, pouring through the connecting tunnel and into the second vault behind us.

This time, the lava was moving much, much faster.

‘If you’re going to stay here,’ said Rozalia, ‘sit the hell down.’

I sat down against the wall just behind Nadia’s seat. I could hear someone hyperventilating, letting out little panicked gasps. It took a moment to realize it was me.

Rozalia drove like a demon, but when I took another quick look at the rear-view monitor, I was far from sure we were going to escape alive. Not only was lava still spewing through from the first vault in a seemingly unending tide, but the vault around us was showing every sign of collapsing. I saw chunks of rock and dust come tumbling downwards from the roof.

We passed through a mercifully unblocked connecting tunnel into a third vault. The headlights picked out signs in Icelandic. A fountain of dust erupted somewhere to our right, signalling, I assumed, the collapse of some building or other.

‘Straight ahead,’ said Nadia. Her fingers stroked Rozalia’s cheek. ‘We’re nearly there.’

‘I can see it,’ Rozalia muttered through gritted teeth. ‘Almost there.’