Based on the photos, "smash their way out" appears to mean "open the door with the clearly marked manual override level", and "stranded" appears to mean "had to cross a couple tracks, and walk to the nearest gap in the fence".
The text of the article suggests they had to use the emergency windows / break stuff, and that they were stuck in a tunnel without a pedestrian evacuation route (which would be illegal even here in the US where we hate trains).
The real screw up was probably lack of training of the people on duty. They should have evacuated the train (i.e., opened the doors, and had conductors guide the passengers with flashlights) after an hour, at the most.
It should also be noted that the London underground (the space underground, not the rail system) is extremely convoluted as people have been building stuff there for centuries.
The text of the article suggests they had to use the emergency windows / break stuff, and that they were stuck in a tunnel without a pedestrian evacuation route (which would be illegal even here in the US where we hate trains).
The real screw up was probably lack of training of the people on duty. They should have evacuated the train (i.e., opened the doors, and had conductors guide the passengers with flashlights) after an hour, at the most.