His unemployment and healing go to his master - שבתו ורפואתו לרבו
צער and בושת obviously belong to the master. נזק and שבת also belong to the master however the חידוש is that the master need not feed him. The reason for mentioning קוטע יד עבדו is that the master retains the שכר of צערא דסמא חריפא.
And if you will say, if he wants he can throw a גט to him - וכי תימא אי בעי זריק ליה גיטא
We can either say that the act of the שליח receiving the שחרור is no חוב because the master can free him regardless, or that the act of שחרור is no חוב since the owner can make him a ספק משוחרר, or an עבד ישראל which is even worse that a ודאי משוחרר.