In this last section, the original melody is now played in the bass, and the vocal is a "background" over it (an octave higher than represented in the playback here).

The last five notes are artificial harmonics . . . fret the notes an octave lower than displayed (around the 12th fret), but place your index finger on the string at around the position of the 24th fret (or where it would be if you had one), and pluck the string with your middle finger a couple of inches away from the index finger toward the bridge. Move your fretting hand and plucking hand together . . . if you move up a fret, move the plucking hand a little closer to the bridge, and vice versa.

What you are doing is plucking in the middle of the "shortened" string" with your fretting hand acting as a "movable nut," so you are plucking in the middle of that "shortened string" to sound the harmonic.