In a squat building just beyond the line of check-in counters at Auckland Airport's international terminal is ''its real-time brain''.
The Operations Centre has four shifts of around nine staff who watch a bank of screens to monitor movements of 20 million passengers a year around every corner of the airport.
They have visibility over nearly every part of the airport, monitoring it with 1000 CCTV cameras.
And in the nerve centre they see almost everything.
Asked whether emotional airport farewells or reunions develop into something more passionate very often, landside operations supervisor Ebrahim Cassim is discreet but says it happens ''quite a lot'', especially in cars.
Sometimes the airport's security team is dispatched to intervene and they follow a strict set of protocols - which he's not prepared to share.
While that's part of the job, most callouts for security or airport trouble shooters in terminals are for medical events and unattended parcels or baggage.
There can be up to 20 unattended items a day, a time consuming task to monitor and ensure they aren't a threat.
There are around 10 to 15 medical events a day. The centre also works with aircraft carrying sick passengers to assess what sort of medical staff will be needed when the plane lands.
It's possible to track any single passenger's movements through the airport with the cameras and sometimes do as part of police or border agencies' operations.
Recordings are typically kept for 30 days.
Facial recognition to help speed passengers' progress through the airport is used overseas and is being considered for use at Auckland.
The control room is next to the emergency operations centre with a large screen and boardroom table and that facility comes to life in cases such as a serious security breach earlier this month when a passenger tried to avoid screening to retrieve a cellphone.
There are levels of aircraft emergency, from a local standby where other emergency services are notified through to a full emergency that triggers a full turnout of the airport's fire rescue fleet.
Pilots have the final say over what level of emergency is declared.