I think "Walk" is stretching it. http://en.wikipedia.org/wiki/Myst: "The player moves the character by clicking on locations shown on the screen; the scene then crossfades into another frame."
So, just like Google Streetview, with way fewer, way higher quality images.
Back to the 'rabbit out of the hat' subject: I found the 3D view in iOS maps on an iPad way more a 'rabbit' thing than I found Myst a rabbit at the time (the first city I saw it was Rome. I looked at a few others, but still think that is the best)
