[Jensson]

Sounds like a bad train system. That has never happened in my experience where I live, and I used to take the subway everyday for over a decade.

[SllX]

Same. The only time the operator leaves the cabin where I live is when they're switching which end of the train they're driving from or they're taking the train out of service at the last stop. There's almost no other reason for them to ever do so.

[hdgvhicv]

When they have to lead an evacuation of the train, for example if there’s a derailment.

[SllX]

We haven't had a derailment here since 2009 where a train left the track by about a foot or so. It could happen, but in the course of normal business operations, evacuations are not a regular event here pulling operators out of their cabins. More likely is a door breaks (or rather someone breaks a door) and they have to seal it manually to keep the train moving, but I only see that happen on the older >20 years old stock and pretty much never on the newer stock.

[hdgvhicv]

The incident I was thinking of was about 2007 at Mile End.

Sure it’s rare. But what happens when it does happen, last thing you want is passengers self evaccing onto 3rd/4th rail energised tracks.