The important thing here is that you do not release the sparkies, and you move quickly.
You can make their chambers smaller by deleting a far left block, dropping into the space, and creating a new block down inside the sparky chamber. In general, build the block as the group is moving to the right. If you find it impossible to build inside the chamber, you may have to "reset" the chamber. But beware, this will take a big bite out of your time.
Do this enough, and you'll limit them to a much smaller area, leaving you the necessary two block column available to descend to the key and return to the door.
