I have plenty of fire alarms, both local and remote, and extinguishers of different types around, I'm not too worried :) But thanks for the concern kind stranger!
The other thing to do is discharge it, so it has little energy stored to maintain/enlarge a fire
A drone engineer I worked with would immediately put any suspect battery into a barrel of water for several days, then get them disposed of properly.
The risk really seems trivial, probably because of our extensive experience with ordinary alkaline and NiCad batteries with a very benign degradation pattern, but the risk with Li-Ion is no joke.
All your fire extinguishers will do you no good if it goes off while you are out of the house. Also, the fire extinguishers will only suppress the surrounding fire, and do nothing about the core Li-Ion fire itself.
Very applicable example for the thread!