What do you think the authors purpose is in having a man help Eliza escape even though he is a friend of Mr.Shelby?

Mr. Symmes hates slave-catchers and feels that Eliza has earned her liberty, so he tells her where she can seek shelter. In my opinion, Stowe uses Mr. Symmes as an example of how different people felt about slavery, and that their views crossed the line of friendship.... she uses Mr. Symmes as an example of those men, who were honorable.... those who saw slavery as morally wrong, and who were unafraid of following their beliefs.