Because of his reckless fighting. Sanami layed in the pharmacy bed with a big wound on his stomach from a previous mission. His head was turned away from kanae who was sitting in a chair right next to the bed. He insisted that he was "fine" and "didn't need help" but she only insisted back that she "needed to treat his wounds" and "give him medicine" but he didn't even let her touch him. So she just waited beside him until he would eventually cave in and let her help him.

Why do you even bother?... He grumbled.