While playing Der Riese I noticed in the room that has the single green glowing, whatever you call it for the hidden song easter egg, there are 3 smaller red ones.
When you go to the one on the desk next to the big green one, press X (playing Xbox 360) sometimes the character will say something positve (using Richtofen) like 'Yes YES'. Then I try to go to the other two (on the shelves in the same room)and press X and he says nothing, then after a certain amount of time if you go back to the original one, press X, he says something negative (similar to the groan the character makes if you try to buy a 5th perk). I'm doing this solo so I don't know if it requires other players to press X at the other two beakers simultaneously.
One theory I had was that there were 3 dead mice laying in the room on the opposite side, and as per each beaker, there was a corresponding mouse that you would go find and press X, but I only find two mice.
*while playing around with this I have currently played the hidden song (the 3 green glowing tubes) and completed Samantha's hide and seek. also I through a monkey in the furnace to hear it scream and listen to Samantha get pissed off because I've never done it and thought it was funny.
Anyone else have any clue about this?