Multiple realities(covers information from several alternate timelines)
Emergency hand actuators were small devices used to open doors aboard Starfleet vessels in the event of power loss.
They were stored at convenient locations near turbolifts, Jefferies tubes, and other vital areas. Use of the device involved attaching it to either side of the door, then pulling the door open. (TNG: "Disaster", "Starship Mine"; VOY: "Macrocosm"; Star Trek: First Contact)
Seven of Nine took such an emergency hand actuator from behind a panel to gain access to a Jefferies tube where a chroniton torpedo crashed inside the hull of Voyager. (VOY: "Year of Hell")
Captain Janeway also used such an actuator to gain access to Deflector Control. (VOY: "Year of Hell, Part II")