This is a fish person, doing a swim. This bit goes on for ages. It's like they forgot they were making Doctor Who and said "Let's just do anything for a bit." It's quite fun.
You watch it, and you think, "Maybe nothing matters. Maybe this is just how things are."
Here Doctor Who is experimenting with yet another hat. This is his least successful, I think, and I reckon he knows it is.
The guy in the background has an awesome head garment though, doesn't he? But he's wearing it as if it's just normal practice to do so.
It's not. This is why, in a bit, their whole civilisation will collapse and everyone will drown.