Alien (1979) was scripted to have a scene where the xenomorph was almost trapped by Ripley and Parker in the airlock of the ship’s “B” level. It escaped but lost a limb in the process, leading to its acidic blood causing critical decompression. Due to budget restrictions, the scene was not completed, but here is a partial moment of Lambert reacting to the situation, which was filmed before the decision was made to leave out the scene entirely.

Lamberto takes the flight without pumping or bearing down👽 | Alien Mast

Alien explained (1979) - Film Colossus