Another way this movie could have ended...(spoilers)

I think an equally effective and more ironic ending would have been this...

As Cushing's character Namaroff dies, his sword slides down the stairs to Pauls feet.
Seeing the Gorgon in the mirror and remembering Prof. Meisters account of Perseus, he picks up the sword, takes aim in the mirror and swings backwards.

And then has to deal with the fact that he has decapitated his girlfriend.

In fact, watching the movie for the first time, I was expecting this very thing to happen.