Board Thread:Manga/@comment-32377911-20170628234245

I just finished the latest chapter. When I was rewatching EP12 of S2, Reiner said Eren is the worst person to have the coordinate abilty. Why is that? and also why did Marley started to attack the walls even though the king threatened to 'flatten the earth'. Sorry I might have missed or misunderstood somthing.  