Living in the 80's is wreaking havoc with Alex's libido as much as her wardrobe. Maybe it's something in that cheap wine she seems to spend so much time drinking at Luigi's.
She can't understand why her unconscious is so very obsessed with the image of Gene Hunt snogging Sam Tyler for all he's worth. If she ever gets home, she's going to need serious therapy, and she hopes her psychologist-to-be doesn't end up masturbating compulsively to a second-hand fantasy.
Sam's dead, Gene is an hallucination, but Alex knows the love is real.
She's seen the writing on the wall.