The one star is purely for Jenna Coleman's incredible performance at the end. This is perhaps the most confused metaphor I've ever seen. It's as if Steven was completely sat on the fence for the whole episode, refusing to share his true opinion on the subject right until the end. Then, when the time finally came, he pulled out a comically obnoxious drill and mined straight down into the core of the Earth (which could also be an alien egg for all we know) where he burned and so did the chance of me ever looking fondly upon this episode.