The train operator can do that to save time. Once a Passenger Alarm is
operated they will inform the line controller, who will call station
staff to attend. If the Train Operator can look out and see where
assistance is needed, they can pass that on to the controller to save
time. Unlike more modern stock, until the Operator is on the platform
they have no idea where or what they are going to confront.

Once the Train Operator shuts down the train to go back to investigate,
an orange door incidator light illuminates above the car concerned and
a Sonalarm will be heard.

If an alarm is activated between stations, the operator will, depress
the acknowledge pedal, make their PA, inform the controller who will
get station staff out at the next station.

The biggest pain in the arse is if the train stops half in, half out...

All in all, a good operator in my opinion

Adrian wrote:
Jonathan Morris ) gurgled happily, sounding much like
they were saying :

The incident today just struck me as odd, even if there's a logical
explanation that I hadn't thought of (as there often is in these
cases). I just thought you keep the doors shut and open one as and when
necessary. It's not as if someone falling ill would, or could, suddenly
run off and take themselves to hospital. So, the doors opening makes no
difference to them. It certainly could make a difference in another
situation.

If the problem is somebody trapped in a door - and in this case, I think
the OP said that the doors had just been closed, so it's fairly likely - or
if somebody's having a panic attack or similar on a very crowded train,
then opening the doors would help.