There was a music video about Mistress 9/Hotaru/Sailor Saturn to the song "In the Air Tonight".
I never knew that but it does sound like it would definately fit.
I found a new song that could fit in many different places much like a few of the other songs. The lyrics reminded me of the different times Usagi and Mamoru were separated or became separated.
It's called "Against All Odds". Here are the lyrics:
How can I just let you walk away, just let you leave without a trace
When I stand here taking every breath with you, ooh
You’re the only one who really knew me at all
How can you just walk away from me,
When all I can do is watch you leave
Cos we’ve shared the laughter and the pain and even shared the tears
You’re the only one who really knew me at all
So take a look at me now, oh there’s just an empty space
And there’s nothing left here to remind me,
Just the memory of your face
Ooh take a look at me now, well there’s just an empty space
And you coming back to me is against all odds and that’s what I’ve got to face
I wish I could just make you turn around,
Turn around and see me cry
There’s so much I need to say to you,
So many reasons why
You’re the only one who really knew me at all
So take a look at me now, well there’s just an empty space
And there’s nothing left here to remind me, just the memory of your face
Now take a look at me now, cos there’s just an empty space
But to wait for you, is all I can do and that’s what I’ve got to face
Take a good look at me now, cos I’ll still be standing here
And you coming back to me is against all odds
It’s the chance I’ve gotta take
Take a look at me now