Hester becomes acquainted with the captain while she was helping the poor. That is why people see no problem with her talking to him while she books passage for herself, Dimmesdale and Pearl. However, Chillingworth must also have noticed the conversation, or the change in the minister's deameanor. He talks to the ship captain also and books passage. Then the captain tells Hester the "good news" that they will have a doctor on board because Chillingworth will be going on the journey as well. For Hester, this means her plan of escape is greatly endangered.