‘I wasn’t sure,’ said Paula firmly. ‘No one can ever be sure. I mean, in my job, I’ve always had to deal with the randomness of what happens to human bodies, the uncertainty, the unknowable stuff. In the face of that—the chaos of it—you try to be logical. I mean, if a patient comes to a doctor with a problem, the treatment can’t ever be a hundred per cent the right choice. All you can do is weigh the risks and choose the most effective course of action, accepting it’s not ever going to be perfect. I think an imperfect fix is better than doing nothing. Better than sitting back and watching harm done—watching the damage you’re fairly sure is going to happen.’

Paula stayed on the sofa with an odd stillness, speaking with an unnerving fluency, while Anita paced and lurched around the room.

‘This is so messed up,’ Anita said. ‘I can’t—I can’t believe … Can you hear the deluded shit you’re spouting at me?’

Anita could hear herself sounding strident and unreasonable. Which was crazy, given that Paula was the one killing people. Which was, by most measures, a pretty unreasonable thing to do.

‘How come you’re allowed to set yourself up as judge and executioner?’ Anita was almost yelling now. ‘You do know that’s wrong and egotistical, don’t you?’

Paula nodded. ‘Yes. But look, if Matt was standing in front of us now about to kill Stacey, you wouldn’t hesitate to kill him to protect her, would you?’

‘Well, of course not. But that’s not what you did.’

‘No one got here in time to protect Stacey and Cameron and Poppy. What if we’d had a chance to kill him before he had a chance to hurt them? If we’d seen Matt walk in here with the rifle, we could have a pretty good guess at what he was going to do. It was the same with Ian Ferguson—he was going to strangle Rochelle to death one day soon, to the extent you can ever be certain of anything. Same with John Santino. I killed those men because it was very, very likely they were going to kill those women. We were too late to save Stacey, but—’

‘Stop saying “we”. This is you. This is fucking you, Paula.’

‘Sorry. You’re right. It is me. And I’m not trying to convince you to approve of what I’ve done. I just want you to understand why I—’

‘This is such self-justifying bullshit. On this basis—what—you draw up hit lists of dangerous people and kill them?’

‘Of course not. But if a situation falls across my path, if a woman is in front of me and she’s—’

‘No. No. This is wrong. It’s so wrong I don’t even have enough words for the level of wrong.’