5th Chest? My count must be off or something...

There's the first chest at the opening of the first dead end room. The second chest at the end of the north most tunnel before going down to the teleporter room. The third chest in the offshoot tunnel before the ogre. The fourth chest from the Ogre. I could have sworn there was a fifth chest in the Captain's Quarters, we got the Alpine jacket there I believe. The sixth chest in the Drake room. Does Batraal drop one?