I presume you'd say that a "regular" office fire is little different from a "regular" fire in a domestic highrise.
As the contra-argument to yours that they do not generate "extreme heat", I hold up Grenfell Tower
It is interesting to understand why, indeed, there were very high temperatures generated at certain times during the Grenfell Tower fire. It occurred as a result of the use of water!
Grenfell Tower contained window frames made from polyester (PMMA- polymethyl methacrylate) powder coated aluminium. When these reach a certain temperature, this amalgam becomes lethal in the presence of water. A chemical reaction producing extreme heat plus hydrogen gas is the final result following some preliminary reactions. Indeed, a somewhat different aluminium mixture in combination with water is used as rocket fuel! There are already some papers outlining this, and more can be expected in the future. Note that, in spite of this, the relatively flimsy Grenfell Tower (compared to the massive World Trade Center buildings) suffered no loss of structural integrity.