‘Yeah, that’s just it, isn’t it?’ Estelle leans forward and looks at me intensely. ‘A lot of other doctors don’t have mates like ours. They just exist in their own heads, no one to booze with or laugh with or, you know …’

‘Cry with,’ I supply.

‘Yeah. So what I’m saying is that we can never let each other down, okay? We have to drag each other over the line, kicking and screaming, to the bitter end. Like when we were in medical school, remember?’

‘I remember.’

‘And if one of us is ever trapped, or going mad, or about to lose the plot, we just have to reach out to the other person and we’ll be there for each other, no questions asked. It doesn’t matter what we’re doing, where we are, whatever fucking important thing is happening in theatre or whatever—we will drop everything and go to each other’s rescue.’

Our eyes meet. I recognise the fear and confusion in her look because I feel it too. We’re both teetering on the thin wire we are standing on as junior doctors, gripping each other’s hands as we try to stay upright in gale-force winds with no safety harness.

‘I’ll never let you down, mate,’ I say to her, feeling an almost ridiculous urge to burst into tears. ‘We will never let each other down.’

My phone rings. Without thinking, I answer it.

‘Her potassium has been low for two days and you’ve ignored it,’ the Smiling Assassin snaps.

‘I told you about it on the round,’ I say, attempting to defend myself, just for something different.

‘I don’t think so.’

‘I can assure you I did.’

Estelle gives me a double thumbs-up and mouths, ‘Fight back!’

‘I can assure you that you didn’t.’

I feel my frustration levels rising. ‘Remember? It’s only four point zero so you said to start her on oral potassium and recheck tomorrow. That’s why I charted the slow K.’

I internally thank the Lord that it’s Friday. Even though I’m on call over the weekend, it means a reprieve from the Smiling Assassin.

She doesn’t answer, and instead ends the call.

‘No time for goodbyes then,’ I say to the phone.

Estelle looks amused. ‘What a bitch.’

My phone beeps. Ah, back to the text.

Ward, it says.

I show Estelle. She looks confused.

‘Ward what? Maybe it’s a typo.’

I explain that when the Smiling Assassin wants to meet me on the ward she doesn’t call or send a text like Would you meet me on the ward? or even Meet me on the ward, she just sends a one-word message.

‘She’s really minimalist,’ I explain. ‘Very word economical.’

‘It’s like you’re a dog!’ Estelle says, torn between laughter and horror. ‘Like: “Fetch!” “Sit!” “Stay!”’