When Per'dra fled, Light wasn't immediately concerned. This battle was well in hand. Upon the final kill, he detected movement and turned to see some flashy Sith do a few flips before landing.
When the Sith threatened Avriela, Light started to advance on him, but he had turned away before he could get there. "The hell..?"
The guy ran off. At first Light thought Coward but then he realized the direction he had taken was similar to that of Per'dra, and began to start off after him. He paused, turned, and called out to the members of the team that would be with him.
"To me! We have a new foe to face!"
Without looking to see if they would be with him, he took off at a run to catch up with this stranger. He wasn't using the Force to speed himself up, as he intended for the others to be running with him, including Corsail. Consequently, he quickly fell behind, though he wasn't out of sight of the runner.