Ronster said:
Nah it is but it intercuts with Lambert listening on the Intercom and Parker in the Corridor.

There is one shot in the trailer that proves that a part was filmed which has Ripley running through the smoke.

The Box Alien as you call it is just moved to the ending sequence instead of the failed attempt. You can see the airlock behind the box Alien.

This happens quite a lot of old films from the 70’s including Star Wars, moving shots about into other locations like R2-D2 on the death Star shots spliced ib when he is flying through Space on the millennium falcon.

It is easy enough to sort the chess game out then Later C3P0 tangled in the wires aboard the tantive cuts to R2D2 on the death star again laughing… If ypu were going to do a special edition that is a worthy cause for changing something or making it work.

The Alien corridor outtake footage is not from the deleted Parker, Ripley & Lambert air lock scene repurposed.

A B/W workprint exists that composer, Jerry Goldsmith used to score the film. Originally, Ripley got a good look at the creature when she turned the corner, seeing it squatting, she ducks back behind the wall and has a SECOND PEEK. The Alien has already risen to its feet, sensing Ripley, it turns in her direction as she ducks back and edges away from the corridor, dropping Jones.

Watch the THE BEAST WITHIN: THE MAKING OF ALIEN documentary and you will find an outtake of the adult Alien hunkered in profile as the camera (Ripley’s POV) rounds the corner and sees it.

You can see the air lock behind the Alien in the corridor as it swings around in the final film. You are meant to see the air lock - just beyond it is the shuttle.

A strong clue, being the emergency lighting and smoke used in the shots of the Alien in the corridor - naturally, as these deleted shots occur during the 10 mins countdown.