A search

Baffled, you step into the room, looking into its shadowy depths but seeing no sign of life. There is no door except the one you came through, and you would have seen anyone exiting through the windows. Your logical mind tells you that there must be another means of escape from the room and you look around, searching the floor and walls for any sign of a hidden door.

The floor appears to be solid concrete, and you see no sign of any trap door. Three of the walls are fieldstone, and you could see from outside had no interruptions except the door you came through and the two small windows. That leaves the back wall, which is of rough planks. Tools and hoses hang on it, and it appears to hold no secret door, but your mind says that a door must exist and by process of elimination it must be in that wall.

Your curiosity fully aroused now you push at the wall in various places but get no response. It seems that the three girls have simply entered the building and disappeared.