The only thing is, in this case there was no fire. Indeed my understanding is there wasn’t even smoke, just a strong burning smell.
These trains have always given out burning smells at times. In times past it was common, if not standard, practice for drivers to get the speed off the clock between High Barnet and Totteridge southbound, which with heavy braking from potentially 60 mph would give a very strong burning smell. Although the trains have regenerative braking, this relies on the traction current system being able to accept the regenerated energy, otherwise it reverts to being dissipated as heat. It doesn’t take too much imagination to consider what this smells like if the driver has just slammed the brakes on full service from 60+ mph, especially if there’s some dirt on the resistors. This particular practice is firmly in the past, but it’s still possible to heat up the brakes on these trains at times.
I have a suspicion that the bigger issue in this incident was the fire panel on the station being put into evac by people pressing call points on the platform (from where any burning smell would have been very evident). The panel going into evac puts an evacuation message on the station PA which is designed to sound urgent, and of course which people on the train would have heard.
For their part, LU do not publicise much information on what to do in an emergency, which is quite surprising really. Indeed certain trains used to have quite detailed posters - the 59 stock certainly did, and so did the 92 stock when new. By contrast the information displayed on the 95 stock is pretty basic. It isn’t something many passengers give much thought to, which is always going to cause a problem on the rare occasions something does happen. One day LU are going get burned by this IMO