Continuity mistake: A few moments after Pike and his group leave the room because they didn't find prisoners, Octavia pulls her own head out of the hole and says "all clear." Then she pulls two machine guns out of the hole with both hands and puts those guns on the left and right sides of the hole separately. In the next shot, those two guns aren't in the same position. Both are in front of the hole near each other. (00:28:58)
Factual error: It is repeated several times the Diyoza was a Colonel, but then proceed to say that she was a Navy SEAL. The rank of Colonel doesn't exist in the Navy. She would be a Captain O-6.
Continuity mistake: When Clark walks into the hall full of dead grounders and it shows her looking at them. A guy on the right moves his head slightly as if getting comfortable. (00:18:50)
Character mistake: Bellamy calls Monty "Murphy" when they get back to the Arc and he is losing oxygen.
We Are Grounders: Part 2 - S1-E13
Factual error: After the Arc goes to earth, the chancellor is sitting in a floating ring in space that no longer has any centrifugal motion. He should be floating, but he is seated and gravity is apparent.
Plot hole: In s04e06 Clarke, Roan and Bellamy are chasing the Azgeda that stole the vehicle with the barrels, killing them all in the process. That leaves 3 drivers for 2 vehicles. S04e07 kicks off with both the rover and the yellow truck re-entering the camp. However, in later shots we see that both Roan and Clarke are at the island and only Bellamy drove home. If so, who drove the yellow truck back home since no other character returned from the island? (00:01:45)
Suggested correction: Different truck. The goal of the mission was to get the fuel (on the yellow truck) to Abby. Early in episode 7 as Clarke and Abby are talking, Clarke mentions that Roan is unloading the fuel. Meaning they still delivered the yellow truck to Abby as intended (minus the empty barrel). So it could not be back at the camp with Bellamy.
Revealing mistake: While Echo, Monty, Harper, Bellamy and Emori are heading back down to earth, you'll notice that Emori's face tattoo is on her right side of her face rather than her left.
Other mistake: In first episode Wells apologizes for locking up Clarke's dad, then acts surprised when she tells him he got executed, when in episode 3 it's revealed they both assisted in the execution.
