Vernon wrote:
The report I had from someone who was on it was that it took staff
about ten
minutes just to get the doors open hence my concern about fire
safety.

There is a way to open a specific door instantly (by using the door
emergency open button / lever) as explained in the safety notices which
are now on all trains. It's worrying to hear that you haven't noticed
and familiarised yourself with the poster because it could well save
your life.

The staff on the train taking 10 minutes were quite probably trying to
open all doors at the same time (to prevent a crush) and to not have to
use the emergency releases (because the train would then be stuck in
the platform until fixed)