User blog comment:Miskos3/Fairy Tail Chapter 488: The Two of Us, Always, Review/@comment-3285005-20160606152200/@comment-9595671-20160607065230

I agree, Makarov is the type to hide things because the truth is more harmful otherwise, or because he knows what'll happen if the truth is known.

Such as in the movie, he knew telling Erza what would happen to Eclair if she killed the Phoenix then she wouldn't do it, so he lied to her about it. I feel if there's any reason Makarov wanted Mest with them, it was so they could teleport away if things got bad.