It doesn't matter what faction you are on the Tantive IV, but an engineer or a heavy class works the best. By the electric turbines, there is a small console with glowing screens on it. Normally, if you walk between the turbine, the electricity will instantly kill you. Now, if you destroy the screen, the turbines will deactivate and you can go through them as the energy field is now gone. If you use a fusion cutter to fix the screen, you an reactivate the energy field and fry any unlucky units that happen to be between the turbines.