Well it depends,do you want to know everyone on the servers role,or do you want to know the roles of players in your "lobby"?I don't play the game but you might succeed by recording the packets sent to you from the server as you login, sensibly that information would have to be sent to you when you join a game, and maybe there role. I don't play the game, but I might look it up later.
[EDIT]
I looked at the game, so it's a mystery game where you have to guess someones role? Sounds all server sided in that aspect, packets probably won't help you, and it's likely not possible but you can try, I don't have the game or money atm to buy buy the game either. Maybe a more experienced hacker could help here, but I don't think it's possible.