Because you never dropped your weapon, you never went off target. Period. She doubted he had a gun – because he would’ve pulled it out and started firing by now – but even if he did, you never lowered your aim.

Sachs rested the sights on the new moon of his head. It was an easy shot with a static target but he was walking backward and sideways and kept ducking behind the hostage.

‘No, please don’t hurt me! Please!’ the woman cried in a low voice.

‘Shut up!’ the unsub muttered.

Reasonably, Sachs said, ‘Listen, there’s no way you’re getting out of here. Raise your hands and—’

A door nearby opened and a slim man in blue scrubs stepped into the corridor. It was just enough of a distraction to draw Sachs’s eye for an instant.

And that was enough for the unsub to seize his chance. He shoved his hostage directly toward Sachs and, before she could sidestep and draw a target, he crashed through another doorway and vanished.

Sachs was sprinting past the woman in the navy suit. Terrified, she stared with wide eyes, backing up against the wall.

‘What was he—?’

No time for back and forth. Sachs flung the door open and peered in fast. No threat, no target. She shouted over her shoulder to the woman and the medico, ‘Get back to the lobby. Now! Wait there! Call nine one one.’

‘Who—?’ the hostage called.

‘Go!’ Sachs turned and eased through the doorway the unsub had just disappeared into. She listened. A faint click – from below. Made sense; he wasn’t going to escape from the upper floors. Unsub 11-5 was their underground man.

Sachs hadn’t come here on a tactical mission so she didn’t have a radio but she pulled her iPhone out and called 911. It was easier than going roundabout to Central Dispatch. She reported a 10-13, officer needing assistance. She supposed the hostage and the hospital worker might be calling too but they could also simply have vanished, not wanting to get involved.

Down another flight of stairs. Steady but slow. Who’s to say the guy hadn’t clicked the ground-floor door latch to fool her and then returned to snipe away with the pistol he did, in fact, have in his pocket?

Sachs had never thought this trip would actually end up in a sighting of the unsub. She’d come here simply to see if any staffers had spotted anyone fitting the perp’s description. Rhyme had speculated that there might be an attack at this hospital. Terry Dobyns’s profile was that, as an organized offender, the unsub would plan the attacks ahead of time. That meant some of the trace they’d found at the Chloe Moore scene might have come from the sites of future poisonings.