Optimus Prime brings down the control pillar, deactivating the space bridge. Dylan reactivates the bridge, then the pillar gets tackled by Bumblebee, which FINALLY destroys the bridge but takes Cybertron with it. The bridge could have been stopped only once, with Cybertron being consumed by the black hole. This would have made Sentinel even angrier, and would have shifted the battle to fighting over Earth now as it was the only world left for the Decepticons. Stopping the bridge twice was a little too much IMO and besides all it did was set up a fight between the Autobot/Decepticon agents.