Joel is watching the hallways carefully, Tessa up ahead while Ellie and you are between them. He doesn't trust what the Fireflies are doing with you two. They continue walking but freeze when they hear a Clicker.

Ellie: What the hell was that?

Joel: Shut it, kid.

Tess: Clicker, hide.

Tess takes Ellie and hides in a room. Joel yanks you into the closet and covers your mouth with your hand. The Clicker approaches, making its sounds and slowly walking down the hallway.

(Your mother was bitten when she was pregnant with you, so the Infected, Runners, Clickers, and Bloaters see you as one of their own. You look and appear human despite having their instincts. Fireflies took you because they think you're immune. You and Ellie are like sisters)