Rein's group and the city lord were planning to meet inside a dilapidated house that was a no entry zone for the citizens. This house was supposed to be affected by a dangerous magic experiment and was contaminated by harmful mana. So coming here was not good for health.
But all that was actually a lie. This house was a place prepared by the city lord to hold secret meetings. Even though the house itself was unsuitable to host reputable people, there was an underground basement in this house which was very well decorated and suitable for hosting even the members of the royal family.
That was exactly the room where the meeting between the city lord and Rein's group was taking place. All three of them were enjoying the best possible treatment that this place had to offer while having a pleasant conversation with the city lord himself.