Some people were allowed to leave the ship freely. She wants to as well. Why was she not offered the chance even though she helped you? These are questions that demand answers. She doesn't want the life of a pirate.
Update 1: She realizes she's in a debt, she wouldn't want to cause trouble after what you'd done. She'll stay
What do you do?
Caio: Only the untrustworthy were let go. I'll try to appeal to her by pointing out the friends she's made on the ship, the rewards to come and if need be, the fact that we saved her from a far worse fate if Plugg had remained captain. (Diplomacy 11) Diplomacy failed, drat. Time to intimidate her by reminding she owes us. (Intimdate 18)
Baolo: Decision about her permit to leave ship is made by Caio
Corwin: Why didint she spoke up earlier? because shyness? im willing to let her go if she truly feels like she needs to go...
Arhalien: hmmm... oops.. Didn't think any of the old crew would like to abandon ship.. Let's have Caio persuade her to stay, we need experienced and reliable crew. And even if she wants to leave, isn't Port Peril a better place to leave ship?