IGN’s Guide to sneaking your way through Dishonored: Death of the Outsider non lethally in Low Chaos. Continuing in Mission 3, Billie finds the Main Vault locked in an inaccessible elevator, and finds a way to access the controls without getting caught.
For more guide help, check out the Dishonored 2 Wiki at http://www.ign.com/wikis/dishonored-death-of-the-outsider