It is not anyone's fault that the ship cast her off. She tells Mia this, firmly, and tells Mia not to go with her or follow her, to make sure the ship gets to its port, and asks Jewel to do the same, please - they'll see each again soon, and she can tell Jewel might make the difference.
Casting her off might make the difference. Their divination had said she was drawing bad fortune on them, and they're not wrong that she's cursed even if they aren't at all thinking of the right curses. It makes sense for them to do, she tells Mia. She doesn't mind.
(Of course you don't, Mia says, but Mia does as she said.)
It's quiet, here in the little makeshift boat. They didn't give her anything but they didn't take anything from her. She watches the sea as it moves between its blacks and blues, and the sky as it goes through its orange-browns. She can see the storm coming.
The little boat drowns first but it doesn't take her very long.
And then (in hand-woven blue-green clothes which dried though her hair is still wet, and the echo of a cough even though her body is fine again) she is somewhere else.