‘Anyway, what do you mean?’ I continue. ‘They’re either dead or not there? Why would they be spending all this time and effort on a rescue effort if that was the case?’

Rick shrugs. ‘The search – it’s pointless, isn’t it? They sent the boats out on the say-so of some woman who’s been in the posh bar chugging champagne all night – hardly the most reliable of witnesses. And if someone did fall, there’s almost no chance they would have survived. Look how high up we are.’

I look down at the water again and it makes my stomach lurch. It is indeed a long way down.

‘Falling from the height of the bar – fifteen storeys – on to water is like falling on to concrete,’ he continues. ‘Chances are you’ll hit the side of the boat at some point on the way down, and unless you land on an awning or something, that’s unlikely to be a good thing.’

‘Grim,’ I agree.

‘And even if by some miracle you land in the water alive, the ocean is enormous. The likelihood of you being found and rescued before you drown or die of hypothermia is negligible. Stopping a ship like this isn’t like slamming the brakes on in a car. It takes several minutes and travels at least a mile before they can even start turning it round. Plus we’re a long way from land. And as well as all that, have a guess how deep the Caribbean is at its deepest.’

‘Erm … couple of hundred metres?’ I venture. I don’t really know anything about the sea beyond the occasional episode of Blue Planet I’ve watched when I’m not on shift which is almost never, but 200 metres sounds pretty deep to me.

He smiles. ‘You div, Alice. You’re way off.’ He pauses for dramatic effect. ‘More than seven thousand metres.’

‘No way!’ I am genuinely surprised.

He nods sagely. ‘Yep. And that’s not even as deep as it goes in other oceans. When you have a minute and the WiFi’s working for more than a couple of seconds at a time, you should google the Mariana Trench. I can’t remember exactly where it is but it’s under the sea somewhere. If you were able to put Everest inside it, the peak would still be two thousand metres below sea level. Imagine that.’ He pauses again. ‘And then imagine being in a body of water that big, all alone, in the dark, after you’ve fallen from this height.’

I look down at the water and imagine someone falling into it and sinking, sinking and sinking. Ugh. I shudder. Doesn’t bear thinking about.

‘How do you know all this stuff anyway?’ I ask.