most older blocks have been rewired, most of those have used plastic coving like this

most older blocks have been rewired, most of those have used plastic coving like this
By Phil Murphy

The bulbs seen here in my hallway would quickly fail if exposed to heat from a fire anywhere in the flat, it would then be in total darkness. The same heat would quickly melt the coving and the (potentially live) wiring drops down, unseen in the darkness, and is strewn across doorways at head/neck/chest height.
This very scenario is not uncommon and has been quoted in a coroners' report following an inquest into the death of a firefighter, as having occurred and contributed significantly to the firefighter being effectively trapped inside a burning flat. It is not known whether electrocution was also a factor  in that case but it may have been.