Stone

"Well, at least we have a map, because the closest point of interest has multiple turns and forks in the road to get to it." Devotion said, looking at that map. "Does someone that isn't me want to navigate? I'm shit at directions."

"I got it." Alex said, taking the map. She pointed to a certain tunnel entrance, labelled with the letters "GW". Now that Devotion looked, each tunnel had a few letters above it, marking what the tunnel was. Among them were CR, CW, A, and PR, as well as many others. Devotion did not recognize any of these abbreviations. He looked at the door he came in, and saw it was marked ME. Me? What did that mean? Maybe it was called ME because that was where Cobb lived, and he was labelling himself? Regardless of what they meant, these labels were the only way of telling which tunnel was which on the map, and how Alex knew which tunnel to take to reach the first and closest Point of Interest, as Cobb called them.