Spitting in the devil's face requires walking into his house.
Horum might not be the devil but Zane would spit on his face anyway. That's why he entered his house.
The door was locked but Zane's ring opened the door with no problem and since the door opened easily, the Wardens who were even a little suspicious drifted their gazes.
If they were thieves, the door couldn't have opened that easily. It would have made some kind struggling sound.
Also, they didn't see Zane using some kind of lockpick on the knob as well.
The man simply went to the door, touched the knob and the door opened.
Either the man had the key or he was simply the owner of the house.
The Wardens were only supposed to look after the houses they were paid for or to stop any kind of disturbing activity happening in the city.
Though, they weren't standing in front of houses because they wanted to protect the people, they were standing because they were paid for the very same thing by the rich.
