On July 18, 1855, Johnson passed word to a black porter in Bloodgood's Hotel, where Wheeler had locked her in with her children, that she wanted to escape her master's custody. He got word to William Still, chairman of the Vigilance Committee of the Pennsylvania Anti-Slavery Society, who helped fugitive slaves. Later that day, as the full Wheeler party prepared to board the ferry, Still and abolitionist Passmore Williamson, secretary of the Society, reached the docks. Williamson told Johnson that she could choose freedom according to Pennsylvania law. While Wheeler argued, offered her a promise of freedom, and tried to prevent Johnson from leaving, five black dockworkers restrained him, and Williamson explained the state law to him. William Still quickly escorted Johnson and her children away by a coach, later taking them secretly to his house. He never told Williamson where they were, under the principles of compartmentalization used by the Vigilance Committee.