Six hours later, the high-pitched wail of an alarm didn’t wake her up because she hadn’t yet fallen asleep.

Her mind didn’t race at night, because that would suggest that it could eventually tire itself out – no, her mind fizzed like nuclear fusion, something with an infinite capacity to continue fizzing no matter how late, or early, it got.

The overhead light blazed into life, nearly blinding her. Squinting and disorientated by the sound, Thea scrambled out of bed, not sure what was going on, but pretty certain she didn’t want to be in bed to greet it. Rory appeared as she was fumbling with her slippers. She felt herself blush under the bright light, awkward in her sensible pyjamas. He yelled something she couldn’t hear above the pounding, painful sound of the alarm.

Rolling his eyes, he came into the room and took her arm, leaning in close. For some reason, she was acutely aware that her pyjamas had penguins on them. In scarves.

‘SO SORRY! FIRE ALARM! WE HAVE TO GO!’

A few minutes later, Thea was standing in the clinic car park in her fluffy slippers, damp spreading into them from the wet ground. The building itself was a drab blot of grey behind them and the street lights turned the puddles to gold.

Rory had unplugged her but there had been no time to unstick all the patches and wires, making her look like the unfinished science experiment that she was. Other members of the sleep trial and their attendants milled around, making polite small talk and exchanging sympathetic glances.

‘So. Do you come here often?’ A man in shorts and a T-shirt nudged her, his feet bare and turning a mottled purple from the cold. Varicose veins bulged up on his skinny legs like inquisitive worms. He was obviously pleased with his wit.

Thea didn’t like being nudged.

She tried to avoid eye contact with him, but he moved in front of her, an expectant grin on his face. Thea turned to stare at the chain-link fence.

She heard the man sigh. ‘It don’t cost anything to be pleasant. Cheer up, love.’

Thea took a deep breath.

Heat whooshed, not over but through her. She felt as if it could shoot out of her eyes like she’d seen in superhero films. If she looked at him, she could turn him to ash.

Cheer up, love. Be pleasant, even if your brain feels as if it could ooze through your nose. Smile, even if this might be your last chance to get help and you are wasting it out here in the car park wearing soggy slippers. The nice man wants a pleasant conversation. Be nice to the man.

It was a well-known side effect of poor sleep, wasn’t it? Recklessness. She’d read that somewhere.

What happened next, therefore, wasn’t strictly her fault.