Vader’s Star Destroyer would then have turned its attention to Leia’s craft, setting up the opening moments of the original Star Wars, but the film would focus on the debris of the destroyed vessel, where the audience would learn that Jyn and Cassian had made it into an escape pod, which survived because it looked like just another piece of debris.
The Empire continued to pursue the vessel that the plans were on while the Rebels frantically tried to copy the data onto Princess Leia’s ship.
According to Entertainment Weekly, they would have been successful in getting the data to the princess, but just as they were, Vader’s attack would have breached the shield’s of Jyn Erso’s ship and destroy it.