The thing to note is that I believe this footage was taken when the trucks were tackling the resurgent fire, after the evacuation was long over.
Did the truck crew know that? Did their chief? Did anyone?
It really doesn't appear to be a case of them arriving at full speed to potentially save hundreds of lives, and getting mixed up with some runners in smoke and chaos, leading to an unfortunate casualty: it looks like a case of driving about gently, with guides on foot, many minutes later.
It also doesn't look like a random city fire truck turning up to help, and being out of its trained comfort zone, since it looks like it had a huge foam monitor on the front.
There's been blood…
Now there will be lawyers…