I think it was recycled footage from Series 6 Episode 7 petrol station fire along with the fire creeping along the tarmac. Good spot watched it hundreds of times never noticed that.
I'm surprised the remfs went in b4 Blue Watch got there as it was called in as an explosion. And they'd need 4 ambulances as the remfs r now casualties due to smoke inhalation as well as 1 4 the original casualty plus his brother was then also suffering from smoke inhalation.