After a longer serial with The Daleks, I found The Edge of Destruction to be a nice break. It follows a pretty standard plot of paranoia (I was reading in some parallels to Cold War era anxieties) and mystery around being trapped—which you can definitely see the influence of in future bottle episodes i.e. Midnight, Amy’s Choice, Wild Blue Yonder. It doesn’t drag too terribly but it’s a fairly unremarkable serial. I did enjoy the start of the ongoing mythology surrounding the TARDIS, establishing that it thinks. Barbara was the standout for me in this episode, I loved getting to see more of her cleverness and self assurance as well as her developing relationship with the Doctor at the end.