There is an extra verse that was cut from the studio album, but nevertheless appears on its sleeve:
"Do I have to stand up
Wild eyed in the spotlight
What a nightmare Why!
Don't I turn and run"
After this, the line "There must be some mistake..." starts.
The full song was performed live in concert, and as such appears on Is There Anybody out There? The Wall Live 1980-81
Javier - Corpus Chisti, TX