"Bloated" Doors Question

[Cyber]

Fire doors are rated for a certain amount of time and temperature.

 

tHANKs

 

I found it interesting that the same deformation is on both the sliding fire door and the rollup door one floor below. That's why I wondered if it was heat rushing against it if both floors flashed over...or just warping from long-term heat exposure and gravity formed that bowed appearance.