The movie: Stone escapes the ISS in a Soyuz, then hijacks the Shenzhou docked on the Tiangong-1.
Real life: First of all, where were the Chinese astronauts (called "taikonauts")? If they escaped, why would there be a Shenzhou still attached to the station? We're also asked to ignore Stone's amazing ability to perfectly pilot two spacecraft that even she admits she crashed in simulation.
On top of that, the Tiangong-1 station is nowhere near as big as it was depicted in the movie. It's actually barely bigger than the Shenzhou. China plans on slowly adding new modules to the space station over the coming decade, but right now, it's a modest orbital work-in-progress. Picture courtesy of: טל ענבר.