She knew that fat round countenance with the moustache like a dirt mark under the nose. Two years ago he had come into the hall of her house and arrested her father. Next time she saw her father he had been dying. This was Inspector Thomas Macke of the Gestapo.

You killed my father, she thought.

Now I can kill you.

It would be simple. She would give him four times the maximum dose of morphine. No one would notice, especially on a night like tonight. He would fall unconscious immediately and die in a few minutes. A doctor who was almost asleep on his feet would assume his heart had failed. No one would doubt the diagnosis, and no one would ask sceptical questions. He would be one of thousands killed in a massive air raid. Rest in peace.

She knew that Werner feared Macke might be on to him. Any day now Werner could be arrested. Everyone talks under torture. Werner would give away Frieda, and Heinrich, and others – and Carla. She could save them all, now, in a minute.

But she hesitated.

She asked herself why. Macke was a torturer and a killer. He deserved to die a thousand deaths.

Carla had killed Joachim, or at least helped to kill him. But Joachim had been kicking Carla’s mother to death when she hit him over the head with a soup cauldron. This was different.

Macke was a patient.

Carla was not very religious, but she did believe that some things were sacred. She was a nurse, and patients put their trust in her. She knew that Macke would torture and kill her without hesitation – but she was not like Macke, she was not that kind. This was nothing to do with him: it was about her.

If she killed a patient, she felt, she would have to leave the profession and never again dare to care for sick people. She would be like a banker who steals money, or a politician who takes bribes, or a priest who feels up the young girls who come to him for First Communion classes. She would have betrayed herself.

Frieda said: ‘What are you waiting for? I can’t gel him until he calms down.’

Carla stuck the needle in Thomas Macke, and he stopped screaming.

Frieda started to put gel on his burned skin.

‘This one’s only concussed,’ Dr Ernst was saying of another patient. ‘But he’s got a bullet in his backside.’ He raised his voice to talk to the patient. ‘How did you get shot? Bullets are about the only things the RAF isn’t throwing at us tonight.’

Carla turned to look. The patient was lying on his front. His trousers had been cut off, showing his rear. He had white skin and fine, fair hair on the small of his back. He was woozy, but he muttered something.

Ernst said: ‘Policeman’s gun went off by accident, did you say?’

The patient spoke more clearly. ‘Yes.’