I got the Gold Key and I've talked to Nivius and as I was leaving the crypt, I remembered that there was a room near the entrance that needed a key to open. I tried using the gold key that was under water that opens up most of the tombs, but the key didn't work. Anyhow know how to open up this room and what's in the room?

If you are talking right after you first enter the crypt you need to raise locks skill or find level 2 picks. Save before trying as locks will jam.

however if it jams a set of lockpicks will open it. Just acouple of treasure chests in this room