The little flood outside of the map on cold storage. Bungie.net : Community : Forum Topic Listing : Forum Reply Listing
No, you die as soon as you get out, but you can still explore around in theater, you can also turret glitch into the big pure forum tank, and get inside with the big guy, nothing happens when you in there, because you cant kill him, but you can keep shooting at his head, and have goo fly out.
Hmm.. that would be funny actually, put a spawn in the tube... If you don't mind, don't want to create another topic, but here are some pics I got inside of said tube... and under 0_o