At 1:26:41 Ridley says people were suspecting the cat, so he wanted to keep that paranoia going.
1:28:42 "I wanted the Alien to have a certain fascination and delicacy, uh, like this massive toy coming towards her... um, which was mesmerizing.
He then talks about playing Tomita's The Planets for Sigourny Weaver to act to while Parker dies on screen.
1:29:57 "...and of course making Sigourny a very lonely figure. She can hear the death rather than see the death of the other two. (Lambert screams) Her death is heard ... and it's, uh, probably more frightening by hearing it rather than seeing it. (Lambert's screams end). That was a tough session in the looping stage, trying to get that kind of ... scream. (Ripley finds their bodies). I think what we managed to do with the film was always place the audience in the place of the individual about to die. So I think we somehow touched on something which makes them always very vulnerable to what's occurring which is why I think it's particularly frightening."
No more on Lambert after that.