The assassin looked back, the border wall of the city clearly visible. As he stared at the towering border wall, the assassin couldn't help but be surprised that there was a hidden tunnel like this that they didn't know about.
Now he finally understood the reason poison was used to kill the previous city lord. If the City Lord wasn't poisoned, then even if they had gathered people strong enough to kill him, they couldn't have done anything.
The moment they had passed through the security, the City Lord could've left through this tunnel that no one knew about. And then, he could've had his revenge. The plan to poison had considered a lot of variables.
Although it took longer, it was also more foolproof. The poison ensured that the City Lord couldn't do anything. All they had to do was wait until he died on his own.