What is walking zazen?
A. Every so often your body needs a break from sitting still in one position. That’s the reason for the walking. But your mind needs no break, in fact is happier without a break. By not looking around, keeping “centered,” you to a considerable extent continue zazen as far as your mind is concerned while giving your body its needed change. This is practice as in the answer to Q3, with “walking” for “whole life” and “come what may and whatever you’re doung”.