User blog comment:Hunterinpurgatory/How will Dean get out of Purgatory?/@comment-4554525-20120616231305

its possible that sam might go back to that lab and do that ritual to get them out or purgatory, perhaps castiel knows how to, or perhaps when another leviathan is killled with that bone it reopens a portal allowing dean and cass to come out, either way, im thinking the "big bad" will come out of it