My head is spinning ( just finished the last episode )

first case ( 1-4 ish):
I was pumped, and full of adrenaline, it was crazy and the story was interesting.

I calmed and acted it got solved. And I kinda of didn't have the urge to watch the next episode right away.
The same thing happened with the other cases until around episodes 7-8 ( I think) where the cases got more personal/related to our main characters and I got emotionally attached to them so I was more invested in the drama. It's kind crazy how much I ended up loving the characters when I am not really that attached to the characters of thriller/mystery dramas.

The story was interesting and done well.
Though it made my head spin a few times, it wasn't that confusing.

The last episode was something, the drama suggested so many things, like how the transmissions could have gone to someone else and it was just crazy and I am really happy that he was alive.

I really love how all three main characters had some sort of relationship.
Even though this isn't a romance, the relationship and chemistry between detectives Lee Jaehan and Cha So Hyun was so cute and then Cha So Hyun and Park Hae-young had less of an implied romantic relationship but they had a hot sizzling chemistry and weirdly, I was shipping for both relationships.
( I don't usually ship a person with a lot of people)

I feel like they won't make a second season, but I wonder how they will do the story if they decide to, like there are so many things to touch on but I wonder what they will do the characters with)

I am not unhappy about the open-ended even though I was wishing for a reunion of all three of them but yeah, this is a good drama and it really made me cry especially when our main characters were on the verge of death.