PrettyBird - I've had one of the 'intercom not switched off' situations too!
Was coming back from the US (so had already been travelling for 8+ hours) and had to get a UK connecting flight from Heathrow to Newcastle ( a BA flight).
All was fine until about 40 mins into the flight, when suddenly across the tannoy the Captain )sounding slightly panicky said "Cabin crew prepare for an emergency landing in 8 mins"
Of course we (the passengers) all looked at each other in disbelief and horror, and one of the stewardesses looked shocked and RAN down the plane to tell the Captain to switch the loudspeaker off!
About 30 seconds later, he came back across the tannoy,
"Whoops, folks, sorry about that, well, yes, I have to inform you that we have had a threat against the airline so we're going to be landing the plane as soon as we possibly can at Newcastle."
The cabin crew then went into 'emergency evacuation' mode, telling up that AS SOON AS WE LANDED we had to leave the plane AS QUICKLY AS POSSIBLE, leaving all luggage/bags etc and (this was the bit that sacred the shit out of me..) that as soon as we were on the tarmac we had to RUN AS FAST AS POSSIBLE away from the aircraft (as directed by ground staff).
We were aware that the plane was 'speeding' really fast, and I have never been on a plane that landed so quickly. As we can towards the airport it became clear that we were away from the main terminal - about as far away as possible - on what looked like a disused runway? There were loads of fire engines/ ambulances/ police cars - all with lights flashing etc.
When we landed, the doors were flung open and they were literally pushing people out, saying "Go,go!". On the ground they were shouting "run, run!"
On the way out of the plane I very nearly got into a fight with a middle-aged lady who was trying to take a large souvenir Grecian Urn with her and slowing everyine down.
After that it was a bit of an anti-climax. We were all taken into the terminal and then had to wait for 4-5 hours for our bags/stuff to be recovered.
I foudn out later that there had been two telephone 'threats' made, saying that there would be an explosion on a Northbound BA internal flight at (can't remember exactly, but say) 6.48 p.m.
Ours was one of 2 flights that it could have applied to (another flight had been landed at Manchester).
We had landed at about 6.45 p.m.
(Thankfully it turned out to be a hoax, and there were no explosions)