The movie: Stone manages to maneuver her way to the airlock, and then opens it no problem.
Real life: It might be a good idea to refer to a real space traveler on the relative ease of using airlocks. Regarding the scene, veteran ISS astronaut Leroy Chaio says that "in order to open the outer door of the airlock, you have to have the inner hatch closed and the air evacuated in between. On the American airlock, you could open the pressure equalization valves, and there's a handle outside so you could definitely open the outer hatch. But the trick is, on the inside, the crew would have to have already closed that inner hatch. Otherwise you let all the air out of the station. If the crew configured it that way before they abandoned ship, then yes that could happen."
Unfortunately, the crew would not have configured it that way before abandoning the ship. Who prepares a space station for some random floating astronaut when their ship is on fire? Even the Great Chris Hadfield ain't got no time for that.