Having worked in the lifting industry (I was project accountant on the largest lifting project in South America), equipment like that takes time to deploy, the outriggers are crucial and great care is taken to ensure that they are on suitable surfaces.
Absolutely, especially when you're spraying a tonne of water every 25 seconds at that height.
I used to drive a tilt tray with a company that had a 'heavy haul rotator' combination towtruck and 'semi crane' often used in accident retrievals/rollovers etc as well as being able to lift and pull broken down large semitrailer prime movers- still with their trailers attached...
When used as a 'crane' it had extending outriggers, and they took a LOT of care on placing and levelling it before deploying the boom- not only does the truck have to be levelled (even a few degrees of 'list' can have dramatic impacts on the stability and weight lifting ability) but you have to assess the surface of what you are lifting from- tar is actually quite a poor surface when it comes to 'point loads' (which is what the outrigger feet represent) and can 'punch through', which can lead to the outriggers sinking and the whole thing possibly tipping over...
And that only had a 12m boom fully extended!!!
I hate to think of what a 64m boom with directed 'water jet' on top adding an axial thrust to the top of a couple of tonnes a minute or more would require to safely set up!!!, even their smaller 32m boom versions (which would only be about halfway up to the fire) is over DOUBLE the height of our boom- you don't just pull up and crank it into the sky LOL
(even then there are 'charts' on the control panels door of the rotator, showing how the angle of lift (both vertical angle ie tilt and the 'swing angle' ie off the back is more stable, directly off the sides almost as much, 45 degrees off any corner greatly reduces stability) and the ground 'load bearing' ability for various surfaces...
All carefully checked before they even start moving a single lever, get it wrong and well- you get to have an 'up close and personal' meeting with the ground...
(I got to run with it quite a few times as the 'offsider' aka 'gopher' (gopher the chains, gopher the shackles, gopher the straps lol), you need a LOT of training and certification before you are allowed to actually operate these things yourself...they preferred to have multiple people onsite when it was being used as a rotator (rather than just a heavy lifter) as more eyes means more safety for all concerned)
ETA not ours, but a very similar one, this one belongs to Ron Pratt who has a youtube channel (LOL- I am subscribed to several 'tow company' channels) for those who don't know what a rotator is...
Lifting a school bus on two winches, the car behind it on the aux boom winches, and he has another one at the rear deck as well still free (plus an underlift on the back for towing trucks etc)
That firefighting rig is literally over four times higher (Rons truck isn't at full height or full extension there)