So much has happened in the last couple of episodes that it's been quite the whirlwind. The last episode left us with the shocking news of Sawaki and Kei having potentially gotten together in an intimate way followed up by the revelation that Kei is actually his childhood male friend who changed somewhere along the way. And this is on top of the dominatrix moments by Hasegawa and the girl on girl time brought about by the aphrodisiac. And then you add in that Sawaki's lost his ability to see the bacteria, at least until he's thrown hard against the floor, and you realize the show has been making you smile continuously for awhile now.
There's a nice bit of introspection that takes place afterwards as Kei talks seriously to Sawaki about his position and explains some of what's happened in the recent past. Learning that it was Hasegawa that called out to Kei to help fill her in on Sawaki shows a level of interest and concern. But Kei points out that she wanted to know more than just about his ability to see bacteria, but also about who he is. And Kei even points out that Hasegawa managed to get him out of a few sticky situations recently that could have ended far worse, and that she only showed concern for him and not others that were involved.
A lot of the episode has a kind of lazy and unfocused feeling about it until Kei and Sawaki finally find Hasegawa to talk to her and she showcases them how she can see bacteria too. The glowing mushroom bacteria leads to talking about luminescent oceans and other places where bacteria survive that people might not think about, but it all comes back down to what Sawaki wants to do with his ability, something that they're all trying to keep secret for him. Hasegawa softens greatly during all of this and that goes a long way towards restoring the bond that everyone in the lab had felt for awhile, though there are still some unanswered questions in regards to Kei.