Now that would be worrying on anything more modern than a Mk3....
Seriously, this story
(1) there was a fault - serious enough
(2) the incident was reported to the guard - correctly
(3) the guard let the train continue to the next station rather than stop it in open country - matter of judgement.
Exactly this!
As a Controller, and fully compliant in the Rule Book, if there’s a door open in traffic between stations, the traincrew should be alerted, signaller and control contacted, signaller to make sure nothing passes on any adjacent lines, to confirm no one had fell out and passengers moved out of the affected carriage, and detrained at the next station, train out of service.
That is literally all that will have happened here, but there will always be some sensationalism/exaggeration as to what has happened, don’t get me wrong it is a serious incident.
I’ve had an incident where by a train has lost interlock with a set of doors suspect at fault, now this was between stations, fault finding carried out with no success, so TIS (Traction Interlock Switch) operated, passengers moved away from the coach with set of doors in question and guard to check the doors are still being held. Next station, detrain the passengers, and go forward ECS.
Not one I liked doing (happened to me twice now) operating TIS with passengers still on, but needs must.