The script must have been written months ago but by some sort of magic we were given a villain who was planning to silence criticism with NDAs at the end of a week in which Philip Green has come a cropper for doing just that.
This was the episode in which Naz got her back story and motivation. Now all the members of Team Tardis are fully activated. That goes for the Doctor too- who got a "lonely angel" moment that pulled Jodie Whittaker's characterisation into focus. It's not an easy thing to turn four principal actors loose in space and time and have them all be interesting. When Chibnall's predecessors experimented with multiple companions there was usually at least one of them who was a gooseberry. Chibnall seems to have pulled it off. His secret I suppose is that he genuinely likes people.