1x7 - Fear the Walking Dead: Passage

Colton brings Sierra and Gabi to the tunnel and tells Gabi to go down first. She seems concerned about Sierra, and Colton says he will send her down next as he has to go down last in order to close the tunnel behind them. After Gabi enters the tunnel, Colton faces Sierra and tells her that he is sorry, but he can't take the chance that she will tell anyone else about the tunnel. He raises his gun to shoot, but Sierra reacts faster than he thought he would and she stabs him in the leg. She climbs down into the tunnel while he is recovering.