Complex sentence: Lumen later reveals to Dexter that killing one of her attackers brought her a sense of peace, and she tearfully recognizes that it will not last, and she will have to find (and kill) the others to experience that peace again.
Split into simpler sentences: Lumen later reveals to Dexter that killing one of her attackers brought her a sense of peace. She tearfully recognizes that it will not last and that she will have to find (and kill) the others to experience that peace again.