Arcatraz is very linear, and is easy to stealth, as long as you are careful of the patrols. It is highly recommended the Rogue or Druid have improved stealth from talents, as it makes stealthing past the patrols much less risky. It can be done without any +stealth, however.
You must be careful passing the blood elf corpses, as they are not dead, but just feigned, and if you approach them too closely, they will spawn bugs which may aggro you.
As you approach the large room, you will notice a transparent ramp leading up to the second level. You are going to go up this ramp, but first you want to check to see if the chest has spawned in this part of the dungeon. If you do not see it in the location of the picture, it has spawned further in past stealth-detecting demons and cannot be reached. You will need to reset the instance if you want to try spawning it at the accessible location.
Stealth up the ramp, so you are positioned almost over the chest.
Now, hop onto the side ledge. This may take some practice. At first, I could only make the jump 1 out of 5 times, and now I can do it 10+ times in a row with no problem. If you don't think you are moving fast enough, use Sprint, or exit stealth to make the jump. There is only one patrol who comes up the ramp, and it is a non-elite that any level 70 can kill.
Next, hop down off the ledge onto the lower ledge next to the chest. Make sure you are stealthed while doing this or you will aggro to early and not be able to open it. You will have to drop down at an angle to avoid hitting the overhang and knocking yourself down to the floor. Again, this make take a few practice attempts, but as long as you remain stealthed, you won't aggro anything.
Now, wait for the patrol of WHITE mobs to path by. It is important you let them move away before starting to open the chest, as they could possibly interrupt the cycle and cause combat-lockout of the chest. When only floating mob remains, start opening the chest from the ledge.
As you begin to open the chest, the floating mob will aggro you, but not be able to path to your position and become stuck. You will automatically cancel looting the chest due to entering combat, but keep spamming open on the chest, even though the icon is greyed-out. A very important side-note here is that there are 2 types of floating mobs that can be near the chest. The first is a melee-only type, that can't hurt you while you are bugging the chest. The second is a caster type, who WILL toss direct damage spells at you. The amount of spells varies between 2 and 5, never more or less. Each one does roughly 1500 damage, so if your health is less than 7,500, you can negate this damage by simply bandaging once inbetween casts, using cloak of shadows, or self healing. It is very important you continue spamming "open" on the chest even while doing these actions.
After 10-15 seconds, the floating mob will bug, and reset, getting stuck in it's current place. You will exit combat, and have exactly the amount of time you need to open the chest and autoloot everything, and not a second more.
As soon as you recieve all the items from the chest, you must stealth again immediately. Within 3 seconds, the floating mob will once again aggro you, but this time INSTANTLY teleport to the ledge and attack you. They hit extremely hard, and may kill you. If you stealth, you will drop aggro from them before this happens.
The chest always drops a level 70 green. Sometimes two. Very often it drops a level 68+ blue, very often it drops green gems, and often it drops blue gems, such as Living Rubies and Star of Elunes. I have gotten 3 Crystalforge War Axes, 2 Ced's Carvers, 1 Bringer of Death, 100+ gold, two-dozen super potions, and more from this chest just doing casual runs.
When you are finished looting the chest, you can simply stealth back 30 seconds to the entrance of Arcatraz, reset the instance, and do it again.
