This is what Wikipedia says… Thermal runaway describes a process that is accelerated by increased temperature, in turn releasing energy that further increases temperature…. In chemistry (and chemical engineering), thermal runaway is associated with strongly exothermic reactions that are accelerated by temperature rise. Can’t say I’ve heard of it effecting EV’s so as been said, just media BS or perhaps our old friends the Daily Fail.
It can affect an EV but more likely to be your mobile phone charging on the bedside table all night or kids electric scooters/skateboards left plugged in…. much more common is a diesel runaway but it never gets a mention in the daily wail