‘Diamond Cut’ by Thomas B. Cavanagh. Oceanview, 329 pages, $18.99 The chilling effects of sex trafficking makes for a thoughtful plot in “Diamond Cut,” as Thomas B. Cavanagh shows how vulnerable people can be trapped with little chance to escape. In addition to exploring the ravages of this crime, “Diamond Cut” also works as a story about a woman rebuilding her life after working as an escort, which, she says, almost took her soul. About six years ago, Sandra “Sandy” Corrigan gave herself a fresh start after a harrowing experience as an escort, using the code name Diamond.