During the old republic, a dark wielder of the force was in charge of a mining operation on a remote planet. Gwen Soren had her own apprentice, knowing that he had a power in the Force that rivaled her own. However she had noticed recently a certain unease within him. As they reached the planet Regin, home of dark apprentice Syke Vorshen, he felt a since of regret and compassion. Gwen told him to squash it quickly. She may have sensed his feelings, but he could feels her too and a sense of not only regret, but disappointment and loss. He knew what would come next.
Later that even she requested him to her office where she started to explain her issues where he cut her off and decided to get this over with. Pushing him back with the force he hit the wall and heard the hiss, hum of her lightsaber. Igniting his they went at it. To escape, he convinced her of her power, force pushing at her which she countered, and he let go, letting himself crash through the thirty story window and with the Force grabbing onto a skiff to get away.