All a learning curve although the risks are very serious.
I got my introduction into 18650 cell danager from a puncture of one cell and watched in amazement a jet of fire leap out of the cell and then onto the next. Black smoke, mini fire ball, the odd explosion it was all there.
Set in motion a fire fighting plan and was very glad to have carried out this experiment. I discovered powered fire extinguishers although put the fire out these extinguishers don’t cool the cells, soon the fire returned from a cell that had went thermal.
Water did the final task of acting as a coolant. Do not use water if are in any way connected to mains electricity. If a pack is charging and starts a fire leave the area. Call the professionals. Your life is more valuable than any home.
NB. All carried out in a garden.