CY,V [Micheal and Erica]

Count Yorga, Vampire (1970): Near the end of the film, two of Yorga's female vampire try to ambush Micheal. One of which is Erica, a friend of his that went missing earlier from her home after a blood transfusion. With it obvious now that she's beyond saving, Micheal manages to ward the two vampires back. But Erica oddly doesn't flee like her fellow vampire and gives Micheal the chance to stake her and end her newly undead existence.

Example of:
Cannot Kill Their Loved Ones