EE was attempting to clean up area between brattice and 1 set of air lock doors to install 2nd set of air lock doors & to position scoop between air lock door and brattice. EE was maneuvering the scoop, the bucket dumped the brattice, the brattice was pulled down. EE and 2 others were closing the door when the air pressure pulled down the door pinning 2 EE's against the scoop.