There's a fantastic scene towards the end of this episode which finally sees the inevitable confrontation between Penley and Clent. Leading up to it, one could easily sense the animosity between the two characters as each would vent in the absence of the other, but their fear of this meeting also came through. When it happens, the two men try to start out with civility, but it very quickly degenerates as the performances of the two actors (Peter Barkworth and Peter Sallis) get better and better. Clent, who has guards with stun guns on his side, finally loses the will to continue the argument and orders Penley's (and Jamie's) shooting.
This whole story has been a thinly veiled statement about the battle between science and intuition (the classic battle between science and religion having been decided several times earlier in Doctor Who; most recently a TKO in The Abominable Snowmen). On the side of intuition and nature, Penley and Storr (along with that interloper, Jamie). On the side of science and computers, Clent, his sycophantic assistant Miss Garrett, and the Ice Warriors. In between the two lies The Doctor, who clearly dabbles in both fields and usually sides on the side where the authority doesn't lie.
Speaking of The Doctor, he neatly sidesteps last week's cliffhanger by merely agreeing to answer the Ice Warriors' questions. And he gives up only after the Ice Warriors count to three before turning of the atmospheric pressure in the airlock! At least them get to seven! The Ice Warriors, after looking ominous and looming in the early episodes, have only resorted now to standing around viewscreens in their spaceship, extruding and retracting their sonic cannon (never firing it), and wiping out the odd fur-wearing local. I hope for better things in the finale.