Based on the episode all I got was that he was in a restricted area. That was seen in the security cameras. I am not able to validate who took posters of a wall. I have no way of verifying that or making a judgement on that.
All I am saying it was a risk to go to North Korea and it was a risk he was willing to take. Did he go to the restricted area? If he did that was his decision. No one forced him to go to that floor. That was a chance he was willing to take. He may have felt that nothing would happen to him.
He decided to take this trip knowing the risks involved. Someone else who is risk adverse wouldn’t have thought to enter North Korea to celebrate New Year’s eve. How nice it would have been if he had not been diverted from his plans and had reached home safely. It just didn’t happen in this situation.
At the end of the day he is someone’s son and the family is mourning what happened and his loss.
No one should have to deal with such circumstances. As parents they were helpless hoping someone would be able to save him.