[@Noxious] He was. A 'proclaimed' hero who eliminated a corrupt scum. I assume male and female inmates are separated as compared to prison facilities in real life. At some point, we can consider that they've met at a place where all inmates of both genders are allowed to be merged. Perhaps at the mess hall or a recreational area.  

Relationship-wise, we could say Dach was the only inmate whom Matty spoke with the most. He shared her a lot of stories behind the Capital's charades and how the links of his fiancee's murder were connected to the vice mayor. We can also say that Matty developed a certain kind of friendship with Dach during his time in prison.