Skein's Island - Accessing Mooington?

So, I decided to use my Ninja to kill Baab and Mooington to skip through the Reincarnation quest for my hunter. However, since in the update Skien's Island was revamped, Mooington has become a much harder cow to kill, hidden behind a locked door.

My question is, how do you open this door?

Spoiler: Skien's Island Lore Spoilers Ahead

I figured from the clues I'd gathered from the island itself I'd need to kill Skien and he'd drop a key, but when I killed him he just dropped the chestplate to the set. I've dropped emeralds and other items into the hopper, but none have worked.

 

I think the key is just an NPC key you kill.

 

You have to find and kill the prison warden, he's in his office/torture chamber

 

Ah, ok. Thanks!

 

How? 10char