'You got anything else useful in there?' Clara asked.

'Field dressings. Self-assembly inflatable replacement limbs. Spare ammunition, of course. Emergency rations. I even have some dehydrated water,' he [Strax] added proudly.

'How does that work?'

'You just add water, and...' Strax frowned. 'Hmm,' he said. 'Maybe it's not as useful as I thought.'

'Milton rose to his feet. 'As a medical man, I see that you appreciate the importance of detail and accuracy.'

'Oh, I'm not that sort of Doctor.'

'Oh? A doctor of divinity, perhaps?' Milton's lips twitched as he said it, suggesting he was being less than serious.

'Perhaps,' the Doctor said. 'I'm a doctor of so many things I forget more than half of them.'

'I could throttle you sometimes, you know that, don't you.' [Clara said]

The Doctor sniffed, unimpressed. 'Respiratory bypass system,' he told her. 'Wouldn't do you any good.'

"Not for the first time, she [Clara] felt that there were several layers to the Doctor's emotions. Hidden below the surface layer, revealed in the briefest flickers of expression, was how he felt about things. And hidden below that-- deep below that, and never revealed-- was how he really felt."

'You got any idea who or what is killing these people then, Mr. Strax?' the sergeant asked as Strax stood up.

'No,' Strax told him. 'But I have a comrade who tells me that once one has eliminated the impossible, whatever remains, however improbable, must also be eliminated. Good day to you.'