A little confusion about what this IR camera is actually set to

Corbel states the object is flipping black to white as a result of temperature changes…. He states the dogs are black so it must mean the IR camera is set to Dark=Hot. But just moments later in the same track of film we can clearly see the underside of the vehicles are dark, which to me says it’s shaded and cold….. is the camera flipping modes subtly and that’s giving us the result we see on the object. I’m really fascinated by the whole thing but I’m not clearly understanding this tidbit, thanks!