Gu Shenwei's tracks had been discovered five days ago, and the killers from the Golden Roc Fort took their time to prepare a perfect trap for him.
A few of them snuck into the teahouse everyday, acting like friendly neighbors by greeting the other guests warmly and joining in every conversation. In this way, 17 of them were already lying in wait for the Dragon King when it came to them for them to act.
Of course, real citizens could recognize which of the guests were not from the neighborhood, but they did not pay any special attention to strangers, as there would definitely be guests from out of town in a teahouse. Gu Shenwei was a fake 'neighbor', and thus could not tell the difference between strangers and citizens.