When the mysterious voice is speaking to Samuel it says something along the lines of "mend the rift". If you look up into the sky upon spawning you can see a large area of orange surrounded by what appear to be blue dots. Could this mean Sam(orange) still has some power over the zombies? Or somehow there was a disruption in time or space or whatever that Richtofen caused? Just found it interesting because blue represents Richtofen and orange represents Sam.