Kate takes out Aldo & Justin + Justin is a talker

Out in the jungle, as Kate, Jin, Aldo and Justin are trekking across the island, Aldo says that the others are protecting the survivors from the smoke monster. When Jin asks about the Ajira flight, Aldo refuses to answer, while Justin starts to tell him about the flight before Aldo tells him to shut up.

As they keep moving, Justin stop's Kate from tripping a trip wire. Jin says that it looks like Danielle Rousseau's, but Justin starts to say that it can't be her's because she died years ago.

Aldo is being obnoxious because Kate doesn't seem to remember that she knocked him out at the Room 23 building in season 3. Kate knocks him out, and trips the wire causing the rocks to knock out Justin. She then takes some guns and makes a break for it, telling Jin she's escaping.

We can presume, as we see later in the episode, that Claire set this trap. We'll ask more questions about her later though.