The film""s well-written screenplay (by Borden Chase and Charles Schnee) was based on Chase""s novel/Saturday Evening Postserialized story (in six installments from December 1946 hrough January 1947):The Chisholm Trail.In another voice-over as he leaves the house, Johnny reveals his deep-seated antagonism over the woman and the strain he feels with Mundson, wondering if their relationship is actually sexual:It was all I could do to walk away.Walker suspects that Nick is taking an inordinantly personal interest in the suspect: "What is all this ""Nick"" stuff?"Lt.Harold Andrews (Brian Glover).Ripley was kept in the infirmary, and placed under the care of Chief Medical Officer Dr.Jonathan Clemens (Charles Dance).After being told she was the sole survivor and viewing the other bodies, she feared the "possibility of a communicable infection" (cholera) but no evidence (of the Alien embryo) was found during Newt""s autopsy in the morgue - she drowned as suspected.