"Valentine"?

[Papillon]

I LOVE Straight Back, but I've often wondered if Christine ever rolls her eyes when she sings with Stevie on these lyrics:
"Fingers find the ivory
Keys and a song
Begins to begin
Like a wolf on the run.."
I do understand "In the shadow of my shadow" but the "wolf on the run" lines I do not get.
I wonder if anyone here does & can enlighten me? And no, I'm not being sarcastic. I don't understand, but I want to.