This is terrifying. It brings back haunting memories of researching the Baku subway disaster when I did a presentation on Azerbaijan for geography. It was the world's worst subway disaster, killing 288 and injuring some 250 more on 28 October 1995, and many died from the resulting fire, smoke (and associated toxic fumes), and panic. Disasters in underground railways are thankfully rare, but when they happen ... it doesn't take much brainpower to realise they can easily become very deadly indeed, with fire, smoke, potentially poisonous fumes, and frantic and confused crowds of people all trapped in a very small, confined space. It's not worth thinking about. What really scares me is how the scale of this disaster seems to get worse with each new report I read. Initially, it was just power surges with some injuries. Now we've got numerous explosions with an unknowm amount of fatalities.
To all those reading this in London, I hope you and your loved ones are safe. Prayers and good wishes to all those involved. Here's to hoping everyone comes out alive.