You will need a decently geared rogue for this.
One solid adamantite chest spawns in every instance of shadow labs before the second boss.
It has the possibility to spawn in 2 different rooms.
1. The first room it can spawn in is the same room as the first boss is. It it located just to the right or just to the left of the first boss(who is banished).
You will be required to kill 3 mobs guarding the chest. Sap first mob, blind second mob and kill 3rd mob. Then kill the mob you blinded, then vanish, eat up, and return to kill 3rd mob. It is not easy, but you shouldnt come close to dieing after a little practise.
2. The second room it can spawn in, is in the same room as the second boss. in this room it is either to the very right side of room or very left side of room guarded by only 2 mobs. Kill the 2 mobs and loot the chest! easy!
There is also 1 adamantite or rich adamantite mine spawned in each instance before second boss, so watch out for that if you have mining profession.
I have only completed this chest run 5 times before posting here, but i have completed the 5 times within 30 minutes, got 7 gold from each chest, 1 blue staff(bringer of death), 1 dawnstone gem, 4 green lvl 70 items, and 3 super mana potions. I also gained 18 adamantite ore in these runs since i am a miner.
Imo this is better than mana tombs chest running as they are lvl 70 chests and have better chance of the lvl 70 blues dropping.
any questions will be glad to answer
Sry for post in exploits, shud maybe be in guides, please move to guides if needed. :S