Been watching this thread for a while,.... GUT WRENCHING!
Some think I'm jus overly concerned with batteries, but this example and many similar, plus my own personal experiences have certainly kept me alert and from harms way. That's not to say I've never blown a few in various manners, burst others into a disastrous mess, suffered minor burns, injuries or damages,.... but my concerns have likely kept me from such seriousness as you have experienced.
I now live in year around in a motorhome,... batteries of every sort are a major part of my life, jus as it is with others who may live a more conventional manner. My household storage bank is a major concern of mine that is monitored frequently on a daily basis, as well as the vehicle system,... essentials of my lifestyle and home. I'm extra careful to store other batteries safely and appropriately in my "home", and such storage can be very limiting in a motorhome.
Most concerning perhaps, are those of my computer, phone, other lithium based appliances, tools, and of course,... my e-bike. NOTHING is left to charge without close monitoring. NOTHING is left to run or charge overnight while I'm asleep! Still, I worry a bit of those electronics left "sleeping" and not truly powered off,.... so that means my phone and such are left on designated surfaces overnight. That's also where my e-bike battery rests,... right in constant view even if completely disconnected from anything. I have an outdoor outlet on my motorhome,... so bike battery and tool batteries are often set jus outside when charging, that's where theft becomes something more to worry of.
Overly concerned??? NO WAY!!!