and Saint decides to avoid such thorny questions of her audience's loyalty by writing Cassandra's death as a mercy killing that she herself requests, and Clytemnestra is reluctant to commit.

BZZZZT do not pass Go, do not collect two hundred drachmas.

rather out of left field?) Ariadne's death at the hands (er, eyes?) of Perseus' Medusa-head shield

Do you have any idea why that choice rather than any other from the field of possibility of this myth?