So Dave, Gusto, Shego and Adammon are on a plane, right, when the plane starts having engine trouble. And the pilot says someone will need to jump out, to lighten the load, but there're no parachutes.
So Dave says, "I'm old, I've lived a good life, I'll do it." And then he jumps out the plane.
But the engine troubles continue, so the pilot says someone else will have to jump. Gusto says, "I'm young and heroic, I'll do it." And then he jumps out the plane.
But the engine troubles continue, so the pilot says yet someone else will have to jump. So Shego throws Adammon out of the plane.