Continuity mistake: At the beginning of the episode as Clarke is walking towards the window in the door, her right arm is already injured, but she doesn't actually get that injury until she breaks the window and reaches through the glass, which cuts her right arm.
The 100 (2014)
Episode list - season 1
Starring: Eliza Taylor, Paige Turco, Marie Avgeropoulos, Thomas McDonell
More mistakes in The 100
Earth Skills - S1-E2
Clarke: Follow me.
Bellamy: And why would I do that?
Clarke: Because you want them to follow you. And right now they're thinking only one of us is scared.