If someone's level 99, you don't fuck around and you get friendly with them real quick. At the very minimum you have a full battalion nearby to ask them what they want, and you absolutely don't want them to be worried you might try to off them.
They took the right decision. She's powerful, and she doesn't want ambition. Someone like that is immensely useful as long as you treat them right - ie send them on challenging but not too difficult missions that feel like suicide missions. And someone like that will completely destroy your country should they want it.