User blog comment:Miskos3/Fairy Tail Episode 241: Tartaros arc: Devil Reincarnation, Review/@comment-1359322-20150711141943/@comment-4933386-20150711154139

Anon: The dimension in the card is linked with the world outside. When sho used his magic, the clown( i can't remember) was able to help Lucy in trying to break off the nekoosoku tube if my memory is correct.

Also, when Erza was bound inside the card, Erza used Ikaruga's attack in conjunction to break through. Sooo if the bomb was so powerful, it will most likely break through and still cause an explosion in the guild.