Who is Sandy O'Toole from Without Remorse and what is their importance?

Sandy O'Toole is employed as a nurse at Johns Hopkins Hospital. She cared for Kelly when he was brought in with gunshot wounds. As a Vietnam widow, Sandy takes special care of Kelly, and she even sees him after his release. Sandy is upset when she learns that Kelly is going on a mission to Vietnam. When he calls her from Hawaii, she tells him the police are looking for him. Over the course of the novel, Sandy and Kelly fall in love. In the end, they marry and move to Virginia.