You may recall that Nyssa collapsed at the end of the last episode, and here we see the Doctor constructing a "delta wave augmenter" so that she can get 48 hours of uninterrupted deep sleep -- in other words, Nyssa's not going to be in this story (just like they used to do in the '60s, although this time it's not because Sarah Sutton needed a vacation but because Nyssa was retained as a character late enough in the game that writer Christopher Bailey simply couldn't figure out a way to include her in the scripts he'd been working on). And Nyssa's not the only one sleeping: Tegan also falls asleep beneath some chimes erected on the paradise planet of Deva Loka that the TARDIS has landed on, but unlike Nyssa, we're going to be privy to Tegan's dreams. And they're quite stark-looking dreams, full of black spaces and high-contrast lighting, as someone who the credits call Dukkha (as in the Buddhist word for "suffering", but which also sounds a bit like "Doctor" -- although the fact that he resembles Christopher Eccleston is pure coincidence) tries to convince Tegan to let him take over her body and engages in all sorts of psychological trickery (such as having two Tegans trying to work out which is the real Tegan and which is the copy) in order to achieve his goals. It's interestingly directed, and the moving snake motif is neat; moreover, it's clear when she wakes up, towards the middle of part two, that this is not the Tegan we know -- and Janet Fielding takes full advantage of the opportunity to play something more malicious and sexually charged than what she's been asked to play so far on the show. The only real issue is that it seems disconnected so far from everything else going on.
So that means that the main focus of Kinda's storyline is on the Doctor and Adric's explorations through the forest, but fortunately for the audience it's quite a compelling plot thread. The extraterrestrial explorers on Deva Loka (clearly based on the British Empire, with pith helmets and such on display) have been slowly losing team members, despite the natives, the Kinda, not being hostile. The Kinda themselves are interestingly realized -- it seems only the women can speak, not the men (because for the Kinda, "voice is ... a mark of wisdom"), but they're all telepathic. There are some intriguing hints about the Kinda, but for these two episodes we're confined mainly to the survey team's dome, where Security Officer Hindle looks increasingly likely to crack under the strain of things -- so it probably wasn't a good idea for the commander, Sanders, to put him in charge while he's out. (The fact that when Sanders comes back he's changed from the gruff military man we saw to someone far more benign and passive is also bad news for our heroes, even if right before that we get a great display of Hindle's madness, as the world he's constructed in his head threatens to crash down around him: "Somebody make him go away! Mummy! Mummy, make him go away!")
It's a fascinating madness that Hindle displays; not the usual power-hungry madness that we see so often on Doctor Who, but instead something far more prosaic. He's quite simply desperate to maintain control of things as they spiral away from him (something, it must be said, that Sanders' repeated needling of the man doesn't do much to help), and he's convinced that he's the only sane one around. He provides an interesting contrast to their scientist Todd, who seems much more level-headed. And in the midst of this is the Doctor, who seems to be hiding a probing curiosity behind the feckless charm he's exuding. This makes the Doctor seem very much in control of the situation, even when he's locked up -- one gets the impression that he's simply waiting for the right opportunity to come along, while trying not to upset Hindle unduly. Of course, by the end of part two that hasn't happened yet, and Hindle forces them to open the box that seems to have altered Sanders so dramatically and which he brought back for Hindle to open -- something that the Doctor seems very wary to do...