I don't think it was hiding away in the shuttle because it was dying.  That doesn't make any sense to me.

I do, however, agree that its dragging away Dallas and Brett to turn them into eggs is extremely cool; so much so that I find the whole concept of the queen in the sequel to be kind of a let-down for shunting this idea off and ignoring it.  Aliens is a good movie to be sure but it doesn't always jive with the way things were presented in the first one, or with other ideas that were more clearly stated in the original script.

The cocoon scene in the director's cut of Alien does interrupt the pacing, making it an inferior version of the movie to the theatrical release; but contrary to what many seem to think, it doesn't screw up the pace just for the fact that it exists.  Rather, the reason it doesn't work is because they put it into the wrong part of the movie altogether.  The scene is scripted and shot to happen before Ripley activates the self-destruct, but inexplicably the re-edit places it after, which makes it seem very bizarre indeed that she would stop and have a chat or even bother to torch them at all when the ship is going to explode in a few minutes!  All the logic of the scene goes right out the window with it edited this way.

A proper fan-edit could put it back where it belongs to greater effect; but it would have to take care to eliminate the background alarm sounds for the impending self-destruct from the mix in order to make it work.

According to the liner notes for the Intrada score release, the workprint scored by Jerry Goldsmith did have a version of this scene (and in its proper place), but that Dallas and Brett were nowhere to be found--Ripley only came across alien eggs and growths on the walls, and torched those.  The music cue for this unused version of the scene begins similarly to the also-unused cue for when Kane first found the eggs on the planet, a sort of pulsing 'liquid' sound made by plucked strings recorded through an echoplex.  Like so much of the music Goldsmith wrote for Alien, none of this is heard in the finished film at all, which is an absolute disgrace.