I believe Erin has made some very brave and clever music selections for her and Colin's dances throughout this competition. They always go with the choreography and performance of the dance.
I agree that perhaps Thriller was an odd choice, but we all remember it and I can think of worse songs to do a Paso to (Brendan!!).
I think we should all trust and respect the professionals choices of music, they do after all know what they're doing!