User blog comment:FairyRaven/Fairy Tail Chapter 435 & 436: The Cry of Victory & Memoirs, Review and Commentary/@comment-115.241.39.191-20150518150526/@comment-9595671-20150518152326

Actually I think the reason they couldn't get past the runes had nothing to do with that, I think it was due to Metallicana and Igneel themselves being inside of Gajeel and Natsu at the time.