Forum:Kino Der Toten Character voices heard in Call of the Dead!

I was playing Call of The Dead with four people and when I was in the room below PhD Flopper, I heard banging, then I heard Dempsey's voice asking if I could let them out! Then I heard Nikolia, sorry if i spelled it wrong, then the asian, then I left to tell my friends! I am wondering if it could be a new easter egg, like ascension, you have to free them, or since there are zombies there, group 935 could have made a teleporter there and they teleported there! Who knows?!?!?