Final answer:
Paul was lying stretched out face down on an exercise table when Dr. Yueh entered the room, according to the passage provided.
Step-by-step explanation:
Paul was stretched out face down on an exercise table when Dr. Yueh entered the training room. This can be clearly understood from the passage provided, which indicates that despite recognizing the entrance of Dr. Yueh by the sound of his deliberate steps, Paul did not change his position and remained laid out on the exercise table after the masseuse had left him. The options given in the question include engaging in a battle, preparing a meal, hiding in a closet, but the description provided in the text confirms that Paul was laying down and not engaged in any other activity. This shows the importance of reading the text carefully to understand the context and actions of characters within a story.