The Moody Blues' "The Story in Your Eyes"

I'm listening to the Moody Blues' Every Good Boy Deserves Favour for the first time (I got it for Christmas).  The only song I already know from the album is "The Story in Your Eyes."  I was thinking about it before I even started listening, and I realized something that should have been obvious from when I wrote about the song a few weeks ago.

In the final verse, there's some internal rhyme in the line "And it's certain that the curtain's gonna fall."  To some degree, the certainty is emphasized because of that internal rhyme, like the words' starting to resemble each other represents the inevitability of the end.

I'd noticed that internal rhyme last time, but it wasn't until to-day that I got thinking about why it's there.  Incidentally, there's a Glenn Miller song - "Wishing (Will Make It So)" - that does a similar thing with the same "certain"/"curtain" rhyme.