Tips:

The 3rd floor of Qin-Shi Tomb is called Viper Caves. "This is the place where the caves of man-viper race begin to appear. Formed in stair structures, there are images of vipers throughout the dungeon."

The mobs' level ranged from 90 to 95. This area's also not so easily to find the correct way out, you may be used to it after grinding there for a while lol. Here I've also prepared another map about this floor for you. The Fastest way to 4th from 3rd floor. Enjoy!

It is a nice place to grind level, 4 uniques spawn in this area, respectively in the four different caves leading to the 4th floor.