User blog comment:IamJakuhoRaikoben/Chapter 387: Tartarus Arc: Part 4 - Father and Son, Review./@comment-5233713-20140606175703/@comment-7418318-20140606180033

If he really turns into sand, getting wet might limit his mobility or cause him some other kind of disadvantage. Maybe that's why he took so great care in not getting hit by her power.