User blog comment:FairyRaven/Fairy Tail Chapter 428: When We Take Different Paths, Review and Commentary/@comment-7418318-20150419081221/@comment-25111584-20150419103036

On a more serious side to Mary vs. Virgo ... there's pain and then there's pain. Pretty sure she wouldn't consider whatever Lucy is undergoing a 'treat'. And if Mary ever turns out to be more powerful than Kyouka ... Eheheheheh. That is assuming Pain is her Magic and she has no other skills. Virgo might as well move in to pound her and get her ass handed to her instead. ;D

As B214 said, the seals mp just seal their Magic Power, don't sever the bond or anything. Talking about dissipating Magic, I'm more interested in why the Demons didn't disappear when Face was activated when they're actually Living Magic.