Signal is turning into a bit of everything — supernatural thriller (what else do u call a walkie talkie that operates on its own without batts?!), police procedural and underdog-saves-the-day narrative. Of cos the lynchpin is the piece of equipment — that walkie talkie. If it hadn’t started buzzing, none of whatever happened would have happened. (and we won’t have any show to watch)
But…why and how?
Disclaimer: this blog post is entirely speculative, so if you are looking for recaps, etc, go elsewhere (like Dramabeans).
At this juncture, Signal hasn’t clearly explained why Jae-han’s walkie talkie ONLY works in Hae-young’s presence. (and why only that time? Jae-han’s time of death?) Is it only pure coincidence? If the trashman had hung around his truck that day, he’d be the one to pick up the transmission? Maybe, but I doubt so. Signal already hints as early as ep1 that Jae-han and Hae-young are linked — if not by circumstances (both are policemen), then by characters (both are hotheaded, upright policemen).
And it probably isn’t so much of a coincidence that Hae-young’s first case is the unsolved kidnapping of Yoo-jung, which has been bugging his conscience since he was an elementary school kid. And who should be the detective assigned to the case then but Jae-han. Subsequent cases also invariably link the two together — be it the Gyeonggi-namdo serial rape/murder cases or the more recent corruption case.
Interestingly, the walkie talkie connections do not proceed in a linear time line — from Hae-young’s pov. When Hae-young first spoke to Jae-han on the kidnapping case, it clearly isn’t Jae-han’s first time. I’d notice that Jae-han doesn’t seem exactly surprised that an “unidentified officer” is speaking to him on the walkie talkie, whereas Hae-young is totally lost in the woods. The reverse happens when Hae-young works with Jae-han on the Gyeonggi-nam do cases. It is now Jae-han’s “first” time hearing about Hae-young.
Given the way the communication seems to “favour” Jae-han (though sporadic, Jae-han sees the radio connection to Hae-young as proceeding chronologically), is the walkie-talkie harbouring a part of Jae-han’s aggrieved soul? (since he has not only been murdered, but wrongfully accused of corruption posthumous) [kooriyuki: Gasp, Horcrux?!] His last words to Hae-young before he was shot is “the past can be changed”. Maybe Jae-han is hoping that Hae-young can complete what he failed to do (i.e. haul his corrupted team leader to justice) or even save him from his impending death.
…And so what now?
I’m uncertain whether Jae-han can be saved though, unless Hae-young manages to help Jae-han uncover Director Kim’s corrupt practices in Jae-han’s timeline. Even if Hae-young is to arrest Director Kim in the future, it won’t change the past. The hit on Jae-han will still happen. (and i will get boggled mind on the consequent changes in the present/future)
However, that is easier said than done. One very clear difference between the current (2015) and the early 80s/90s is the level of public tolerance for corruption. In Jae-han’s time, it is easier to keep things hush-hush, as long as you are rich and powerful. More so when police forensics are less advanced and rigorous. Though there is still corruption in Hae-young’s time, police investigations and procedurals have become more strictly enforced, and let’s not forget the power of internet. (kinda hard to completely hush things up nowadays)
In that case, the walkie-talkie may be Jae-han’s last bid to complete what he failed to do.