Tony laughed, a little louder than necessary and felt absurdly guilty in doing so. It was cut short when he saw Peter stoop and lock the classroom door.

‘Do you not trust the wee blighters?’ he asked.

Peter shrugged. ‘You always lock the lab,’ he said. ‘Last thing we need is some little thug turning on all the gas when we’re out of the room.’

Tony nodded. ‘Very wise,’ he said, slowing his pace to allow Peter to get well ahead of him. He knew there was little point in checking Peter’s class. The next door down belonged to the prep room, then a second lab on the far side of that. Both labs could be accessed through the interconnecting doors of the prep room, but it was there, he suspected, that the technician would be having lunch.

He passed the prep room, confirming his assumption with a quick glance through the glass pane in the door. The technician was moving around inside, gathering up apparatus, as far as he could tell.

He moved past the prep room to the second lab and tried the handle. It too was locked. He knew that the doors could be unlocked from the inside; if he could make his way into the lab through the prep room, he’d be able to get back out again through this door.

He lingered a moment at the end of the corridor, then turned and came back again, passing the labs and glancing once more into the prep room. The technician had a grey apparatus tray in his hands and was heading towards the rear of the room, to where the connecting doors into the two labs where positioned. Tony saw him turn into the right and pulling open the door, go into lab 1.

Almost without thought, he opened the prep room door and, as quietly as he could, made his way up to the back of the area. He glanced quickly right to where the technician stood, his back to the open door, unloading equipment at the fume cupboard. Just as quickly, Tony opened the door of the lab to the left and went inside, pulling the door softly closed behind him.

Only when he reached the desk and put his hand on the handle of the drawer did he realise he was shaking, his legs jittery with adrenaline. He puffed a breath, glanced about him, then quickly checked the corners of the ceiling for a security camera. The burglar alarm monitor winked red at his movement and, for a second, gave him reason to pause.

He steeled himself, then slid open the drawer. The thermometers were still there, where he had last seen them. There were seven in total; he took two, putting them carefully into his inside pocket. He slid the drawer shut.

‘Are you OK?’

He jolted around, swearing audibly with shock at the voice. The lab technician stood, the same grey tray in hand.

‘I was covering here yesterday and forgot my book,’ he said, holding aloft the novel which he had been carrying. His initial pride at the speed of his lie was immediately countered by a realisation that, having now seemingly found the book, he had no reason to go into the other lab. ‘I think I left work in here, too,’ he added, rolling his eyes. ‘Head like a sieve, you know?’