I nod. He doesn’t realise that all the nerve endings in my body are tingling and my muscles are clenched as tight as they can go. If he touches my arm again, I might shatter into a million pieces. He glances inside.

‘Here we go,’ he whispers.

I try to breathe deeply as we walk up the stairs to the entrance of the hotel. The electronic doors slide open and a wave of cold air hits me. Matt walks on ahead and I skip to catch up. I look around the foyer, taking in the scene. Maybe this is how a burglar feels when they’re about to rob a place. We have to cross straight in front of the reception desk to reach the lift that will take us to the forty-ninth floor. This is such a strange thing to be doing on a Saturday.

Matt has timed it perfectly. An older couple are checking in and the woman at the front desk is helping them. As we walk past, I glance across and see the woman’s red-lipsticked mouth talking. Then I look ahead to focus on where I’m going.

‘Let’s get changed and then go for a swim,’ says Matt loudly. He’s explained the drill to me. It’s all about pretending; if you look confident enough, nobody will think to ask questions.

‘We should just check Dad’s back in the room,’ I say, remembering the script we made up.

‘And grab our towels.’

Ten metres to go until we’re at the lift. I concentrate on my feet. It’s like I’m running the 200 metres and I’m out in front and I know I’m almost there but I can sense someone right on my tail.

‘And maybe something to eat,’ Matt says (which was my line but I totally forgot).

‘Yeah, I’m pretty hungry,’ I add.

We reach the lift. We both stretch out our hands to jab the button at the same time. He pulls back and lets me do it. My mouth is dry; I try to swallow.

‘What do you feel like?’

I look at him and see something in his eyes. Something new. Something a little scary. For a second, I want to turn and run back out the electronic doors to the street and all the way home.

There’s a ding and the lift doors open. I scramble across to let the people out. Matt’s already in and there’s a moment when I look at him and he looks at me and it would be so easy to leave.

‘Come on,’ he says, and I step across the threshold and into the lift.

He stabs button forty-nine and smiles at me. ‘You okay?’

I nod and force myself to swallow again.

‘Here,’ he says, opening his backpack and pulling out a drink bottle. ‘No backwash. It’s all yours.’