"I Am the Walrus" is probably the best thing, musically and cinematically, to come from the Magical Mystery Tour project. I've always felt you can actually see John Lennon losing his mind during this performance. Yoko Ono would soon enter the picture to make it all better (for John). This is creepy weird (which is the tone of the entire film), at parts, but that's why it's classic Beatles.
I wonder if they had to do any reshoots of that long fade out.