"One click left!" the elves shout. "Oh, and we're doomed!" 

"King Richard!" you shout up the pipe.  "Throw down the lighter!" 

You hear something rattling down the pipe.  You place your palm at the bottom opening of the pipe, and the lighter drops into it. 

"Unfortunately this is the Dark Ages," you say.  "So I have no idea how this works." 

"I do," says Rocky, "since I invented it." 

He clicks open the lighter, snaps his thumb over the wheel, and a flame spouts off the wick. 

With renewed appreciation for Rocky's talents as an inventor, you touch the firecracker fuse to the lighter wick.  Instantly the fuse sizzles.  You waste no time in throwing it. 

" - eeeee!"  concludes the Green Knight. 

The firecracker explodes. 

That's your only option.  I'm not even going to grace an apparent alternative link!