Yeah, you're absolutely right. I kept skipping through the CDs to make sure I wasn't just imagining things, but the song isn't included in the OST. It's one of the best songs on the game and they didn't bother to put it in the soundtrack that's filled with songs that don't even last a minute, kinda stupid.
Anyway, here's the song:
https://www.youtube.com/watch?v=Ryo_Os-sanw