Nah bro ya can chill on that. That priest don't play any role other than what you have seen in this chapter. It was sort of described in the novel that the priests who take care of such vows are like this unable to hear or see things related to vows that they are in charge of. As for how they are able to? IDK. Perhaps they are a special category of priests among the normal ones?
Yeah that's that I assumed. There were two different priests. The one who led them into the room and talked and the silent one who just did the ritual and wrote the instructions on the table. The one in the room with them when they were talking was the deaf one. The priest who spoke to them at the end of the chapter was the one who led them down there.
Hey don't you think the priest is wierd how can a person not listen to a person who is just standing there ?? It feels like he will spell trouble