Ho Gae and Seol ended up together passed the hardest situations and the time together.

"The first responders" compare to two seasons Dex is the most underrated villian in this arc, he is powerful and manipulative committed more murders in Korea and USA.

Ho Gae and Seol romance moments in the final episode is good their chemistry and their love and care between the even in the hardest situations they care for each other, not giving up their love for silly reasons and they pass together in that situations. Compare to some other k drama couples, this couple is different.Ho Gae and Seol relationship progression in S1 & S2 slowly and steadily without rushing things compare to Do Jin.It's not a romance based drama but leads value their relationship in hardest time and not giving each other and give strength eachother.

Overall, drama has unpredictable twist and turns, writer killed even one of the main lead Do jin. It's worth to watch and invest time.