Howling:Merging of universes in Assimilation2

In the Star Trek: The Next Generation/Doctor Who crossover comic Assimilation2, it is evident that the Cybermen have somehow managed to merge the universe of the Doctor and that of Star Trek together (even affecting their individual past histories, judging from the Fourth Doctor's encounter with the original USS Enterprise crew). Any ideas as to how they've accomplished such a fantastic feat? I would have thought something like this would be far beyond the Cybermens' capabilities. And why does the Doctor tell the Enterprise-D crew that the universes will split apart and assume their proper histories once he and his companions depart, and now the Cybermen are all destroyed? 82.20.113.152talk to me 20:43, February 16, 2013 (UTC)