You can read Changmin's interview
here.
And this is a snippet of Tsumabuki Satoshi's (Kouda) interview.
One thing that made him nervous was how to portray a feeling of distance from his friends. 6 people who possess completely different personalities. While each of them is lonely, through working together for the bank robbery, their bonds are strengthened. In them, is his relationship with Momo, a spy for his former country up north. It has been pointed at as having a homosexual element in the original work, but it was a large task figuring out how to portray the vague exchange of emotions between the men as well as how to play Kouda, who is cool and doesn't show emotion on the outside.
"Kouda and Momo each have a different loneliness, and because of how they are similar or how they are not, I think there are parts of them that understand and parts of them that are attracted. In the script, there isn't much about their relationship from the original work, but for me, I acted embracing the idea in my heart that, "I like Momo." Within the short 2 hour span of the movie, different from a novel, it was very difficult showing the distance of his emotions without being gaudy.
There is an important scene that portrays Kouda and Momo's intimacy in a single moment. It is a scene where Kouda casually touches Momo's head as he passes by it.
"That was an ad lib. I wanted to draw out Momo's natural reaction, so I didn't do it in rehearsal. Every day at the movie location, I worried a lot over doing things like this. Although it's a short scene, I think there will be people who watch without overlooking it, so I'm glad."