The first response describes a moment of situational irony: "Captain Auld sends Douglass to Baltimore so Douglass will be more profitable, but in doing so places Douglass in a position where escape is more attainable."
In this case, Captain Auld's intention is to increase his own profit by sending Douglass to a place where he believes he will be more beneficial to him. However, this decision inadvertently provides Douglass with opportunities and conditions that allow for the possibility of escape, which is the opposite of Auld's goal. This creates a clear instance of situational irony.