Our killers get increasingly frustrated in episode ten of "Tunnel - Drama", as the only person on the side of the law who can understand their signatures is Jae-i. Aside from delivering a timeline and recap of the murders, the episode also presents our killers with some surprises. After a conflict with Gwang-ho, Jae-i makes a bold and very dangerous decision about her involvement in the case.
We now have a clearer image of who has been killed by each murderer and we also have a hinted connection, which should bring about some answers soon enough. If Mok Jin-woo (Kim Min-sang-I) has been using ink from the factory of Jeong Ho-yeong's (Heo Sung-tae) parents, then the two could have very well known each other. I do hope everyone's connection will be explored by the end, because I assume that time would have a good reason for bending like this.