Remember that bugged gate at the Mechanar instance report a couple of days ago? The one that unfortunately locks up at times when your party gets wiped out? Well, Blizzard was quick to address the problem, kudos to them. Drysc explained:

We've applied a hotfix to the Mechanar wing of Tempest Keep. The door at the top of the elevator was remaining closed after a group would wipe to Pathaleon, preventing players from completing the instance. The door now properly opens after a group wipe, letting players travel to Pathaleon and kill him.