Scene Edit Detection only applies to source material.

I have a question: In order to perform a Scene Edit Detection, you have to make a sequence of a clip and then do it on the sequence, unless I'm doing it wrong and I don't think I am.  So if you're performing it on the sequence, why is the action made only to the source clip?  This seems illogical.  What I mean/what I need to do is sync a clip up with audio (splits), make a sequence of that merged clip and then subclip out only the synced nat sound.  However all that is subclipped is the origianl source material and its mix, which isn't any help to me.  Why go to the trouble of making this a sequence oriented workflow if this happens?  It would seem to be a reasonable and common task that I'm trying to do.