User blog comment:IamJakuhoRaikoben/Chapter 495: I'm Hungry As Hell, Review./@comment-5672982-20160725171838/@comment-7418318-20160729135519

And how would burying someone alive work when that someone can destroy all the debris that would fall onto him?

Hell Gildarts walks through walls if he's not paying attention, so what's to stop him from just intentionally destroying the rockes ahead of him to make an upward sloping tunnel?

Acutally Gildarts should easily have been able to turn Serena either into a lot of little Serenas or cubes together with his magic, like he did with Natsu back on Tenrou.