That's only if that map is real, however I doubt that as Makarov showed that map. Lucy was always talking about luck and 1/8 chance to pick out the safe path, so if that map would be true she wouldn't have said that as then they would know which was the safe path.
Also you encircled the wrong path of Erza (if you would follow the map). The map says that Erza is on the 4th path starting from the left, however you encircled the fifth path which is according to the map the safe path. Erza's path is the one right above the one you said Natsu entered.