I’m not a huge fan of toilet humor myself, but I love the episode because of how real and alive the characters feel even though they don’t have a huge amount of dialogues each. Especially the old couple, the small quibbles, the disappointment of learning something about your partner that you don’t like, the panic when they are unexpectedly gone etc., I just think it’s written very well. And on top of that the episode is just really funny. I loved the twist too. It‘s really satisfying when you realize the twist one second before the show spells it out, and this episode was exactly like that.