Audio problem: The cabin floor is carpeted, but the footsteps heard are of a hard tiled floor.
Audio problem: Several times during the episode, when someone is walking on a rug, the sound of footsteps is that of a hard tiled floor.
Audio problem: When Buck walks to the bar downstairs and meets Mrs. Oates, the sound of their footsteps is that of tiled floor, but they're walking on a rug.
Answer: In a flashback scene, it was shown that he had a violent temper, so it stands to reason that he finally killed her in a fit of rage.