In re-watching Star Wars: Rebels again, I recently finished season three. Agent Kallus's character arc in the last few episodes seems to confirm a suspicion I had about "The Honorable Ones" (S2E17).
At the beginning of the episode, the Rebels fall into a trap that Kallus has set for them on a construction module above Geonosis. During the subsequent fighting, Zeb gets separated from the rest, and when he boards an escape pod to leave, Kallus follows him. The pod crashes on a moon, and while waiting to be rescued, Zeb and Kallus have to work together to fend off bonzami and get out of a cave. During this time, Zeb encourages Kallus to start questioning the Empire's motives. Obviously, Kallus takes this advice, although not immediately; in season three, he begins acting as something of a double agent (taking over the Fulcrum moniker to feed the Rebels information), and in the season finale, he ultimately defects to their cause.
At the end of "The Honorable Ones," there's a brief moment that seems to foreshadow this change in Kallus. Before Zeb returns to The Ghost, he turns and bows to Kallus. Kallus had been sheltered behind a rock, but he steps out into the sunlight in order to return Zeb's bow.
His coming into the light prefigures the events of season three, as Kallus slowly moves from the darkness of the Empire to the light side embodied by the Rebellion.
Taken an-other way, the sunrise illuminating Kallus's face represents the beginning of his enlightenment. He eventually starts to understand what the Empire truly stands for.
