Obama owes her.
She's taken a lot of fire for the "Sunday Morning" talking points fiasco and she was also Obama's pick for Sec. of State. But, she had to decline, because of the Benghazi dust-up. There is no way she could have been confirmed.
If I'm not mistaken, as Obama's Nat'l Security advisor, she also can't be called to testify in the Benghazi hearings, covering both her and Obama's asses.
Donilon was either asked to leave for Rice's move up, or he probably wanted to get as far away from Washington as possible. Supposedly his wife took a new job out of the country and he is going to fall off the map soon. He knows where Obama was that night of the attack.