I think he should have pressed the button to stop any oncoming trains, then 'ignored the rules' to go and help get her off the track. There were several people on the track helping to rescue her. BBC news says "The nearest train was about a quarter of a mile away when the people were on the tracks." but what if it had been nearer?
I consider it to be same sort of risk as a fire - you ring 999 first then see if you can safely give immediate help.