If air-raid sirens (which we do have here in Switzerland) would start sounding, nobody would seek shelter, because everyone would consider an attack too unlikely.
Of course, in retrospect, it would have been better to call the firefighters first. But to make such consequential decisions three days into a new job requires proper training and clearly defined procedures.
This is actually standard procedure in many places. Security guards often have x minutes to see if it's a false alarm:
* https://gps-securitygroup.com/the-role-of-security-guard-reg...
Non-residential buildings are often charged for false alarms, so the landlord may wish to first confirm if the fire brigade is actually needed. If you work in an office tower, or live in an apartment or condo, you'll often have multi-stage fire alarm system: you don't actually evacuate unless either (a) it's a confirmed real incident, or (b) the confirmation timeout has been reached.
They were using a industry standard operating procedure (SOP) in a non-standard environment. Sometimes it's hard to know the situation is non-standard until after the fact.
>The employee monitoring the smoke alarm panel at Notre-Dame cathedral was just three days on the job when the red warning light flashed on the evening of April 15: “Feu.” Fire.
and
>Finally, the guard radioed the fire security employee to call the fire department. It was 6:48, 30 minutes after the first red signal lit up the word “Feu.”
The message specifying the location of the fire could have been more clear, but the fact that the fire alarm was going off was clear. When you see "Feu" flashing red on the alarm panel, the correct course of action is obvious. The greatest failure was that the guards tried to go find the fire, wasting 30 minutes, instead of just calling the fire brigade immediately.
If a tsunami warning is being sounded, would you go down to the beach to try to spot it first, or would you run for the high ground?
If a warning of a bombing came, would you go outside with binoculars and try to spot the planes first, or would you run down into the air raid shelter?