Evan pointed out in the last post that the we may not have recognized the two girls in the Looking Glass hatch pointing guns at Charlie, but we have seen them before. We believe the blonde to be Anne, Bens childhood friend on the island, and the other to be Cassidy, Sawyers ex girlfriend/con. Cassidy was also connected to Kate when she helped her find her mom and confront her.
Take a look at the screenshot below and you can see pretty clearly that it was indeed Cassidy.
Will she and Sawyer and/or Kate ever come face to face?