He must have been struck by the vertical rather than, like people were used to in Europe, horizontal aspect of life in Tokyo judging by the number of escalators he captured.
The film reflects beautifully on this very point. It's called "montage". Also "filmmaking". You have to pay a bit more attention to what is being articulated through the images and sound and so forth. And watch lots of other stuff and know the author... Eventually you may come to realize your thought process is also an important part of the film itself. Cheers
