Those in power rarely tell anyone everything.

I ain't expected to be special or chosen since I dropped through my first dimensional space-time rift. Probably because it was obvious I wasn't. [He never had the illusion so it never had a chance to break.]

And from what I heard, they weren't just 'like' zombies. They were. And they need to eliminated. And maybe we need to be prepared for the possibility of fighting the remains of our friends, but it sounded like our undead guests were mostly localized to that settlement we found.