You are mixing things.
Yest,it is given that that heat will kill the packs.
But, you may be astonished finding out that if you draw 80% of packs energy and max current is 40% of packs maximum, heat generation is the same, regardless if they are 12S or 10S.

In Andrew's and AC's video they did not show, nor anyone else has shown, any proof or theoretical base to support 12S packs to produce less heat over 10S.