Firefighters have connection to demolition personnel, I believe. There’s a lot of cross-over between firefighters and military lower ranks, and between military explosive handlers and demolition teams. I think you’ll even find that firefighters sometimes use explosives, for emergency access, for blowing out fire, and for removing unstable structures where fire is being fought. WTC7 was just bigger than usual.

And check the Silverstein quote again. He says the fire department made the decision to pull.