We don't know the exact language, but by Timnit's account she made a numbered list of demands, which is pretty inherently direct.
It sounded from her account a straightforward threat to leave.
In any case, making this an issue sounds way overkill.
Both want to part way. Either side can choose an earlier date of the termination.
She doesn't need Google's permission to leave earlier. Google also doesn't need her permission to make her leave earlier.