Does anyone know why the fire truck was driving across the runway in the first place? Was it a patrol, repositioning the truck, or was there an active incident that they were responding to? Seems like reducing the number of times you have to drive across an active runway is in general a good thing, but perhaps at an airport this old this is the only way to get from A to B.

> Does anyone know why the fire truck was driving across the runway in the first place?

Yes we know. There was an other airplane who declared an emergency and was about to evacuate the passengers on the tarmac. The other plane in question had two aborted takeoffs, and then they smelled some “odour” in the aft of the plane which made some of the crew feel ill.

I believe it was responding to the other active incident that the ATC was also handling where a plane failed to take off?

They were responding to an incident (unidentified odor on another plane)