Alternative: You could assassinate Lee Hong while he is in the restaurant. Do not bother picking up the Poison Vial, and do not bother disguising as a Waiter. Instead, Put a few bullets into Lei Hongs head, and then make a break for the Sewers (quickly). To pull this off, you will want to have gathered the weapons and ammo from the "Staff Area" or from the Sewers. You will need to kill a lot of people this way, but once you reach the Sewers, things should calm down. You may want to kill a Guard while in the Sewers, and take their clothes. Even though the Guard may be dressed the same as you are, changing clothes will help to re-disguise you again. Make your way to the HQ through the Secret Passage, and then use the boat to escape. ...