In the last level, the Launch Base Zone, the Death Egg launches off for the second time, knocking Knuckles off a pole and sending him plummeting to the ground.
In the last level, the Launch Base Zone, Sonic travels through to see Knuckles blow up the building that they are in. As the Death Egg launches off for the second time, it knocks Knuckles off the pole sending him plummeting to the ground.