Too many characters. This episode shows that "The 100" is in danger of having too many characters. Now that Jaha is on Aladdin's land, we have the extra "sand people" to take into account. On top of that, there haven't been many "important" casualties in the characters's body count, so we have a very stretched list (we just need some interesting Reapers...). Consequence: characters that disappear. For example, in the previous episode, Raven was conspicuous by her absence.
That's not to say that the episode is a bad one. Jaha's storyline is a mysterious and interesting one, and it remembers us that there's supposed to be people affected by radiation (visible consequences). The "sand people" may be an important part of the show from now on. Or they may be not. But their addition has helped in showing a new part of this beautiful-horrible-dangerous world the people from the Ark have gotten back to.
Anya and Clarke's prison break is also interesting enough. Two strong people, who hate each other but have to join forces against another one. The enemy of my enemy... Are they going to make a real team, is their interaction going to help in the Grounders-Ark relationship? The episode teases us with one and the other, and it is the better for it.
Strangely, there are also some (more than normal) incongruities in things that happen in the episode. But they can be forgiven for now, as the level keeps being good.