1 - Kill every single guard in the level. There's 80 in total.
2 - Free Agent Smith in the basement.
3 - Free Lei Ling for the safe code.
4 - Find the jade figurine in one of the safes in the level. It's randomized as to which one it is.
5 - Give the jade figurine to the old man at the floral shop for the poison. Don't kill him!
6 - Success! Lee Hong and his bodyguard Zhun will personally meet with 47 outside the shop to try and kill him. If you have an AK47, you'll easily be able to gun them down.