After compelting the stone slabs, head back to the man and he will explain that he is stuck under something.
You must be in Eclipse Mode and go back to where (Random Perk Machine) is and all 4 people slide down the waterslide. Everybody must stand still where they landed in the water. If NOBODY MOVES OFF the pressure plate for 15-30 seconds, it will go back to regular game mode.
NOTE: You know if you did this succesfully if it goes back to day time FASTER than normally.