Rocastle turned from inspecting one of the glass statues that the bomb had made of the boys. ‘Ah, Miss Summerfield. I’m glad to see that you survived. Are any of the boys with you?’

Benny found herself chilled by his matter-of-fact tone. ‘Dr Smith got most of his House out. Apart from that, I don’t know.’

‘He ran away, you mean!’ Hutchinson snarled. ‘If he’d stayed at his post, this might not have happened! How many lives do you think his cowardice cost?’

With a great effort, Bernice ignored him. ‘I wouldn’t recommend staying around here. The aliens might be back.’

‘Oh, do we know for certain that they’re aliens?’ Rocastle asked, making a tick in his book. ‘They sounded almost English to me.’

‘What are you doing here, anyway?’

‘I staged a retreat, took a number of my boys out through the dormitory windows and on to the roof of the sheds. Then the explosion happened. Like magic, isn’t it? Quite like magic. Anyhow, after it had all died down, I thought it’d be best to ascertain the casualties. I’m going to have to answer for the life of every one of these boys, Miss Summerfield. The least I can do is identify them.’

Benny couldn’t help asking, ‘What’s the difference between a retreat and running away, exactly?’

‘The difference is, he’s in charge!’ Hutchinson told her. ‘He gives the orders, which Smith disobeyed.’

‘I wouldn’t get so touchy about it. What’s past is past.’ Rocastle waved a hand airily. ‘Smith has some good sides to him. Knock off a few corners and he’d be a solid chap. What he has to do is to concentrate on what’s best, eliminate the negative.’

Benny followed as the teacher and pupil wandered into another glass room, this one full of small statues. Some of them were throwing their hands into the air, some had intensely pained expressions on their faces. The light creaking of the glass suggested somehow that the pain continued, even in death. ‘So what are you going to do after you’ve finished this?’

Rocastle looked up from the register and tapped his teeth with his pen. ‘Oh, I think I shall have to eliminate the negative altogether. Do my duty. I have no future, madam.’

Bernice shook her head. ‘Look, there are other ways to go about these things. We’ve got a party of boys together. Come with us.’

Rocastle seemed to consider it with the same gentle dislocation that had rolled over all his decisions. ‘All right. When we’ve finished this.’

‘If you don’t want to use it,’ Timothy asked, ‘what do you want it for?’

Smith slowly withdrew his hand.