I should've mentioned this earlier (it's been about a week since I beat the game).
After unfreezing the Wizard in the stunt car, I transed out (no walking involved, just straight trans-out if I remember correctly). This very ominous, scary music began playing--it wasn't the Noised Area tune or any of the game's standard "danger" music. It continued playing even during virus battles, and only stopped when I trans-outed again--at which point everything went back to normal.
I dunno if what I heard was unused music, or if it was just a music-corrupting glitch, but I thought it was worth mentioning.