He pulled his own handgun even as she walked away from him; not that he thought for a second that she'd need the back-up, but he's not the kind of guy who believes in wasting time.

When Nat glances back he's already walking forwards, with that fast silent stalk characteristic of government and law enforcement, stepping without pause over the guard's slumped form and into the room beyond.

It's small and brushed-steel glinting with technology; he and the gun look left, right and up and see no-one.

"Clear," he says, steady and almost inaudible.