[BBI45]

It could just have been that either the alert was within the broadcast zone or that there were multiple alerts escalating it. 

I'm sure a long time ago a photo was shown of the Breakfast/NWT gallery with orange and red lights with a caption along the lines of now we know what these are for.

Yup. I'm fairly sure I've mentioned this before on one of the forum's predecessors, but when I went on a tour of MediaCity a good few years ago, you could clearly see the two-stage alarm system that they had in place. Meaning that in theory, a call point or smoke detector could be triggered in one area of the building, and there would be a few minutes to investigate the cause before the entire building got evacuated. In the meantime, it would alert others in the building to prepare to evacuate (hence why in the Tony Livesey clip, he starts to explain the situation before the alarm sounds). 

I do have to wonder now if that's changed or if the entire building gets immediately evacuated if the cause is in a kitchen or canteen? This is at least the 3rd time that it's happened during breakfast programmes and knocked output on BBC One, Radio 5 Live and Radio Manchester off air.

(Or maybe the safety warden is just too busy eating their bacon butty to check in time )