I'll start the brainstormiung.
The implosion story is a cover up and they actually entered the hollow earth through an elaborate system of locks and dams in order to meet with Peter Viereck, who has been reigning over the sub-subterranean ape people as a tyrant since 1952. Using the mystical power of orgonism they will return to the surface and subjugate humanity to build a giant crystal pyramid from which they will fight the Posada aliens. Our Orca comrades are trying to stop them by incapacitating their agents off the coast of Gibraltar.
They faked their deaths for tax evasion purposes.