Sam and Ilona tied the pirates' hands together and left them all in the jungle by the stream. They wouldn't be left to die. They could all untie one another. But it would take some time, and by then, Ilona, Anja, and Sam would be long gone.
Then it would be up to the traitors what they would do next. They could return to the cavern and take their chances with Pierce Vane, or they could take their chances surviving in the jungle without a shelter or a good way to get food. Either way, Ilona felt relieved that she hadn't killed them and added more lives to the list on her conscience.
Unless, of course, they died from the injuries she had inflicted, but she pushed that thought from her mind. They may have turned on her, but they had been her men once, sailing the seas as her crew. Before that, they had been her mother's crew, and she had sailed alongside them. She didn't want to kill any of them if she could help it.