What is Park Joon Mo's intension to kill Jung Ki-chul....

According to doctrine, suicide is considered a sin.The crime may have been replaced by Joon Mo. The consideration may also be directed at his wife Yoo Eui-jung (played by Im Semi).Jung Ki-chul's suicide is a curse aimed especially at Yoo Eui-jung.He is a man who has liked her since childhood.He's a man who tried to get out of the dark for himself.The guilt of driving such a man to death can last a lifetime.Park Jun-mo shot because he wanted to free Yoo Eui-jung at least by taking responsibility for Jung Ki-chul's death alone.

I agree totally , I also thought Gicheul tried to kill himself because he knew how affected she would be and that once Joonmo saw that there would be no reconciliation their marriage , wether he managed to commit suicide of Joonmo killed him he end up cursing them for life

I think their divorce was a mutual decision. Maybe not at first, but as time went on, they both realized that they no longer really had a marriage to fight for. They realized that they grew into different people, and that it wasn’t possible for them to heal and continue to grow together. 

At first I didn’t understand why he killed him and didn’t just shoot him in the arm or leg. But now it seems to me that he still wanted to save him from a great sin (suicide). And their marriage was already predetermined from the very beginning, as soon as they started this game. It seems to me that she still had some feelings for Ki Chul.

 Neha Kiran:

Did she have feelings for him? Both in the past and the present, whenever Ki Chul kissed her, she made a fist as if it was happening against her wishes. I wanted to know how she actually felt about him.

Perhaps it was not love, but pleasant memories of her childhood. And of course she wanted him to become a good person and stop doing bad things.  She cared for him. 

 Veroni4ka91:

Perhaps it was not love, but pleasant memories of her childhood. And of course she wanted him to become a good person and stop doing bad things.  She cared for him. 

I think she just cared about him as a childhood friend and wanted him to live a normal life and not be a criminal anymore. It was obvious throughout the whole show that EunJong did everything in order to protect her husband. That's how I felt. 

I think Jun Mo relates to Ki Chun when he explains how Ki Chun always had the opportunity for a normal life but he gave that up for his greedy pursuit. The same can be said about Jun Mo who began his undercover investigation because of his feelings of inadequacy with his background compared to his wife's. Jun Mo tries to compensate for his insecurities by aiming for great achievements through larger risks. And once shit hits the fan, Jun Mo trudges forward whilst losing his humanity because he feels like he's in too deep to call it quits. This parallels Ki Chun's experience. 

So I think when Jun Mo lets Ki Chun go, he didn't do it because he had an undying loyalty for Ki Chun. Jun Mo, who saw himself in Ki Chun and resented that fact, was hoping that both he and him can restart and return to normalcy. This is why the camera pans after the drug bust, it juxtaposes Jun Mo still wearing Tae Ho's rolex and his wedding ring. The wedding ring represents Jun Mo's past before he went undercover and what he desires to get back, while the rolex represents his undercover life which still affects him; though Jun Mo tries to forget his life as Seung Ho, the consequences linger.

When Ki Chun returns to Jun Mo, defeated and unable to move on and restart, it also foreshadows Jun Mo's inevitable fate. When Ki Chun attempts suicide, he was no longer the criminal on the run, but the man who had a chance at a good life and lost it all in his greedy pursuit and was now putting an end to it. Jun Mo did not want to face his own reality, and by killing Ki Chun, he reverts the narrative as to a criminal on the run. But Jun Mo can't escape reality. While both Jun Mo and Eui Jeong receive promotions, his wife lays a bed of flowers and returns her necklace on Ki Chun's tombstone, to suggest she rejects Ki Chun as merely the slain criminal; Jun Mo lays his ring (which represents his past) to suggest he has fallen in the same way Ki Chun has.