I used to teach at a school where I also trained to be a teacher a few years before
In the intervening period that had a real problem - details later
Anyway - as per usual they had scheduled fire alarm drills - normally the teacher knew about them but not always
(if the kids had been watching they would have noticed that the teachers often had umbrellas and coats at the ready on a day when they knew a test was due - but they didn;t)
Anyways - one day one year group was moaning because it was VERY hot (for the UK) and the girls were all wearing short skirts but the boys were not allowed to and had to wear long trousers - shorts were not an option
It all got rather heated - I know what they meant because I was in the same block a few years later - and they 'held a protest'
which involved then setting off CS Gas
in a clasroom and corridor and leaving the school to block the road
Police, ambulance were all called - and eventually the Fire Brigade as they could ventilate the rooms
all other pupils were evacuated as usual
Except that the corridor in question was no useable due to the CS Gas and they had to go the long way round and exit via a different route
which caused chaos because no-one - teacher and kids - knew where to go
luckily the school had some intelligent people in it (yup - teacher can be clever - mostly) so the whole procedure was reviewed
future drills included random blockages at times and teacher were given new maps with main escape route plus a reserve
On a different point - 'some children' decided at one point that it was 'fun' to set fire alarms off
we had rather a lot
ended up with 5 in one day
at the time I had a Year 11 (aged 16) form group who were rather annoyed as their revision lessons for looming GCSEs were interrupted
and there were some rather big and difficult kids in that group
They were 'rather annoyed' at the time at told me they were going to 'have a word'
which was worrying - and I explained - in words of one syllable - that they were NOT to etc etc etc
at the same time the Head got a company to install CCTV covering all fire alarms
the problem stopped
not really sure which technique was effective - but it is damn difficult giving a warning to a 6 foot plus angry 16 year old when you have to look up to see his eyes
Anyway - problem solved and no one was injured - probably