Oh ok, I read again the first post.
You need to check for a collision between the zombie and the wall. On that collision set the animation of your zombie.
Once it happens, you need to not move the zombie again (so your moving event needs another condition, like a check on a boolean, or an animation already not playing).
And at the end of this animation, destroy the wall, and set the zombie to move again.
Example capx the zombie follows the mouse cursor.