Ah - forgot about the Python one (so much for my stupid avatar)
Yeah, was thinking “Mary”
Never considered those ones (especially “YS” 
) Try another singular one!
Again - that one escaped me (and shouldn’t have). But no.
hint - made-for-tv movie, also - a wonderful band named themselves after it
The first that came to my mind is from The Right Stuff; Gordo is asked to provide a sample as part of the medical screenings before being selected as an astronaut.
…maybe you meant monolith?
Submarine = Das Boot ?
Ah, thanks.
Correct.
A nice, claustrophobic flick if ever there was one.
But the clue was good enough to get a correct reply. :^)
Bingo! Carry On Nurse!
Electrolytes