It seems that Pest has a magical backpack. As the gang pulls out and uses all of his fireworks, in a minute more magically appear.
Just before Biggz jumps off the walkway onto a small truck it shows the drop to the roof of the truck to be approximately 8 to 10 feet. In the next shot Biggz only drops about 5 feet to the top of the truck. When Biggz is on the ground beside the truck the long shot shows the drop is once again 8 to 10 feet.
Just before Pest shoots fireworks out of the weed room, a hand can be seen raised behind Brewis which then taps him on the back. This was, presumably, a member of the crew signalling Luke Treadaway of when he should run forward and kick the door open.