Question: When Kylo Ren tries to use the Force on Rey, he mentions that they need the last piece of the map, and that they have the rest. However, when R2-D2 wakes up, we find out that he had the map the entire time. Was Kylo bluffing or did he know where the rest of it was? Was there a copy or did I miss something?
Answer: The piece of the map that R2 had was also recovered from the archives of the Empire.
Answer: The First Order already has the piece that R2-D2 was carrying as well. That is the first piece, the large piece of the map missing a small section. The second piece is carried by BB-8 and only by BB-8, the missing piece in the map. All the first order needs is that second piece, and so does the Resistance. However the Resistance needs R2-D2 to activate again so he can show them the first piece, so they can put the second piece in it.
lionhead