Jill had one arm over the edge of the pool and Smith knew that she had been down under, checking on his safety.  He had been aware of her when she had done it... but now he knew that she had not alone been worried about his safety; Jill felt other and greater trouble, trouble that was not relieved by knowing that her charge was safe under the water of life.  This troubled him very much and he considered going to her, making her know that he was with her and sharing her trouble.