I was expecting a sand joke right to the end. But it turns out, Arq doesn't like water, because it's salty, liquid and irritating, and it gets everywhere. And he had every right to be afraid of it, since there was a foreshadowing in the beginning of the episode that came true in the end. Also, Arq is officially DENSE now xD
Returning to the sand scene, Zekra's undressing was alsmost erotic by its description.
I very much enjoyed the feel of Lairagh-2's nature. I have always loved stormy weather during the warm period of the year, especially the times when it becomes absolutely dark during the day because of thick rain clouds. And just like in this episode, it posed no real threat if you were prepared. The depictions of the rain from inside a spaceship are also adding to the planet's flavour. I wouldn't mind visiting such place myself (but only for a short while, due to their lack of proper internet).
Speaking of darkness, black leaves sound like a very efficient way of using the sun's energy. Maybe because this planet's star has less short-wave content in its light (or less of it gets through the atmosphere), and the plants have adapted to some form of low-evergy photosynthesis, using a broad spectrum of visible light.
A "mix-oriented main axis" of the Shrindarey is probably the fanciest way to say "taur". Wondering if this species will come up again, with so many engineered useful properties and, um, compounds. Also, alien pronouns.
The scene of Arq nearly drowning and the accompanying illustration were quite horryfing, but his reasoning was surprisingly calm during this moment.
Overall, it was nice to see him get a little bit more attention, and judging by his interest in fancy machineries, maybe he will find more abstract knowledge useful to himself after all.

Maybe there will be some sand joke in one of the episodes featuring deserts.
He also does not like water because he can't swim. And because his spiracles face upwards, which is rather unfortunate when it rains.
Well, it was viewed from Arq's perspective, him being horny for his companion is nothing new.
It was certainly something different from the usual cities and bases. Storms are nice when you don't have to be in them.
The near-black leaves were more an adaptation to living below the tree cover, where it is pretty dark. But I did mention in Ep. 7 that red dwarf star planets tend to have black plants due to the star's low energy output.
Well, there needs to be some suitable nomenclature for stuff that can't be referenced off human culture, also, it allows for more consistency.
It's definitely organs in this case, as Shrindarey are purely biological. They might or might not come up again, but I did make a list of the various possible types of partially and fully synthetic organisms to use.
Well, it's better to keep still when flailing will only shorten your life. Or he simply went into shock stupor.
Nnnot spoiling too much, but him using a highly-advanced device will be a big part later.

Just out of curiousity, I took a quick look at Ep.7, but couldn't find any references to plants' colouration, only to their morphology due to the tidal locking. I can be blind, though, or it may be another instance of hivemind.
Having the airways pointing upward is not a bad configuration for swimming per se (as in cetaceans), but not being able to seal them off is. By the way, I remember an argument stating the particular nose shape in humans has evolved as an adaptation for diving, as the air gets trapped inside and doesn't let any water in. Not sure about how realistic that really is (and it had failed me numerous times when I was oriented with my face up under water).
And yes, storms are only beautiful when you watch them from inside a shelter. Being drenched in water and getting blown away by wind is not too funny.