‘Alexa is great,’ Jack said. His eyes lit up. ‘She’s so smart.’

Ben smiled wanly.

‘But Ellen is great too,’ Jack added, quickly. ‘She’s so funny.’ He looked up suddenly. Ellen hadn’t turned round, although he sort of wanted her to hear this bit. ‘I’ve never really met anyone like either of them before.’

Ben softened. ‘Yeah? Brilliant.’ He cleared his throat. Jack looked at him expectantly, and Ben gave him an awkward smile. ‘Be a great time for that locksmith to turn up, eh?’

Amidst all of this, Jack had slightly forgotten that they were, technically, going to be rescued at some point. ‘Yeah.’ He thought about the Twitter thread again. ‘Um … I think I might get some fresh air, actually.’ He pointed towards the skylight. ‘And maybe,’ he swallowed, ‘see how Ellen is doing?’

‘Good plan.’

Jack stood up. Alexa was still staring at the wall, her slight shoulders hunched. She looked very small, buried there, in amongst all the boxes. Jack walked towards Ellen, who started, nervously. When she saw it was Jack, she relaxed and looked away again.

He waved limply at her.

‘Hey, Jack.’ Although she wouldn’t look at him, she budged up a little in order to make some space for him to squeeze into the window frame beside her.

He joined her. ‘Have you seen the man again?’ he asked, conversationally.

Ellen didn’t reply for a few seconds. ‘No,’ she said, finally. ‘But I haven’t really been concentrating.’

‘No, of course,’ Jack said, in an understanding voice. He patted Ellen gingerly on the shoulder.

As he did so, his phone vibrated in his pocket and he felt a thrill in his stomach. He glanced at Ellen quickly to see if she’d noticed, but she appeared to be staring into the middle distance, lost in thought. From up here you could see across the Thames all the way to the shiny, modern monuments of the City, and Ellen’s eyes seemed to be fixed on these gleaming spires. Jack wondered if he could get his phone out without her noticing. He was anxious that the connection might drop off again before he could see what the notification was.

‘Did you hear any of that?’ Ellen asked, finally. She still didn’t look at him.

‘Oh … no.’ Jack added, ‘Not really.’

‘Good.’

A bird landed on the roof a few metres away. Jack eyed it warily. After a few seconds, it leaped back off again.

‘Are you OK?’ he asked, finally, awkwardly. He knew he probably should have asked that before.

‘Been better.’

‘Right. No, of course.’

The phone! It vibrated again!