This story is great. Jamie - in the skirt - and Victoria - in the trousers - run away from a robot Yeti - in the fur coat, in the background.
"Jamie is saying, "Let's not run directly away from the monster - let's go quite near it." This is because the monster is really slow, and Jamie doesn't want it to get dispirited.
Why are there robot Yeti? You may as well ask "Why did the Cybermen in the last story have tiny robot mice as pets?"
Just accept that they are here, and that we will now spend six weeks wandering around Wales, being scared of them. Or finding them delightfully fluffy. Whichever.