"You Still Believe in Me"

I've been listening to The Pet Sounds Sessions box set again, and I discovered a couple things about the vocal melodies.  While listening to the first disc a couple days ago, I noticed that the end of the line "I try hard to be strong, but sometimes I fail myself" in "You Still Believe in Me" descends.  The "myself" is sung to a melisma (D# D# C# C), so the speaker/singer is literally letting himself down ("fail[ing] myself") in terms of musical pitch.  Additionally, "You Still Believe in Me" is in B major, so that C natural is an accidental.  The foreign tonality there almost represents that "fail[ing]."