Tips:

The 4th floor of Qin-Shi Tomb is called Hall of Vipers. "Formed like a beautiful trail, the Hall of Vipers is where the most powerful normal monsters appear in the Qin-Shi Tomb. In the heart of the Hall is the Spirit of the Viper Hall that takes you to the 5th level."

The mobs' level ranged from 96 to 99. This area's easilier to find the correct way out compared with another 2 floors. The gate to 5th floor only opens 4 time a day, every 6 hours. According to cSRO and kSRO, the opening times are 4:00, 10:00, 16:00, 22:00, Silkroad Standard Time. But I don't know whether iSRO will do it in the same way lol. Here I've also prepared another map about this floor for you. The Fast Way to 5th Floor from 4th Floor. Enjoy!

The mobs in this area are rather strong and all of them have differenet curse skills.