when your Under ground go to the barrier: If you put "stick pistons" on that block the piston will make the block go out of the barrier.

MC:PE bug reporting has been suspended on the Mojira. Please report bugs related to MC:PE via one of the following:

Reddit: http://www.reddit.com/r/MCPE/comments/2asho8/09x_bug_reports_submit_issues_here_and_only_here/

Minecraft Forums: http://www.minecraftforum.net/forums/minecraft-pocket-edition/mcpe-recent-upcoming-pe-updates/1998290-mcpe-bug-tracking-thread

I Reported it now...