Damn, that was brutal. You know, as much as I'm happy those guys got what they deserved, I do feel for all the police and soldiers who got killed. Most of them probably didn't even know why he was doing that. To them, they were just doing their job, protecting people from a crazed murderer, who was also a threat to national security.
Also, I didn't really like his parents either. There was always the possibility of him waking up from the coma. Getting justice for him was fine, but killing themselves for that wasn't. They say they were doing it for their son, but did they even think about what he would've wanted.
Would he have wanted them to die for getting him justice or live and help him get through everything after he woke up. They could've always tried other methods. And even if they failed, and killing themselves was the only way, is putting the perpetrators in jail for a couple of years, worth their lives and leaving their son alone? Did they even think about what would happen to him after they died and he woke up? If that sword hadn't shown up, he would've just lived and died miserably.
Yes, I know this is a manhwa and we wouldn't have a story of that happened, but it should atleast be more believable.