
T-T

People say Bum is like Sangwoo's puppet because he plays with Bum and is in almost complete control over him. In the earlier chapters Bum was always looking for an opportunity to escape, he's stopped that now. He tried to escape during the concert, which didn't work but why didn't he try to escape afterwards? If it was out of fear then why didn't fear prevent him from trying to escape during the concert? By staying around Sangwoo he is giving him more power over his life and his emotions. If Bum develops a dependency on conforming to Sangwoo's wants and needs it might help stay alive but it decreases the chances of him being able to escape and just gives Sangwoo more control over him.
I don't believe Bum saw Jieun as a threat to his life. He was jealous and ,in the moment, wanted Sangwoo's dick. The idea of Sangwoo having sex with a woman is so offputting to Bum because sex with Sangwoo is something he's longed for and never gotten. Remember Bum had a dildo, he probably used it in the past while thinking of Sangwoo. He'd have sex with a woman but not him even after Sangwoo said he wanted them to stay together forever and that he loved him too? Although that "love confession" was probably a lie those words might has resonated with Bum and he may have belived him to a degree. That's kinda saddening to Bum any that's why he started pouting in the middle of the blowjob.

I don't think he has stopped trying to escape. He has simply changed strategy. In the earlier chapters, he wanted so passiona to get out, that he did it in the wrong way. What I mean is that he wasn't being rational, he would just take any opportunity (even bad ones) to do it. He had no proper plan or anything And what he got from that? He got beaten to death. Look at his legs, he can't even walk properly! And he lost Sangwoo's trust And that's the consequence for trying to escape that way. But he got wiser (he would be very stupid to try that again, given what happened). He is trying to be more cautious. What he gains from behaving like this? Sangwoo's trust. Sangwoo is so self-centred, that thinks that everyone would love him and that Bum flatterings are genuine. Moreover, I'm sure he also thinks to be a fucking genius, and to have Bum under his thumb. This is a HUGE advantage for Bum if he wants to escape. Especially because now Sangwoo takes him out (isn't this better than being locked in the house?).
I think here is necessary to draw to distinction between loving someone and having a crush on someone/idealising someone. I mean, I know nothning about love (despite my almost 25 years), so this is just speculation. But I think that when you are in love, you know that person very well. You know their flaws, recognize them as such and accept them. It's accepting the person in their whole, despite knowing they are not perfect. The point now is: Did Bum know Sangwoo enough to be il love with him? NO. So, it can't be love. I know that when you have a crush the feelings are strong the same way, but because it's not love, they don't have the same characteristics. Crushes are developed on the basis of the good qualities people possess (not on their whole personality). Bum thought of Sangwoo as handsome, kind, whatever else... probably he never even conceived the idea that he might have a dark side or some flaws. But he has and the gap between the idea he had of Sangwoo and the real Sangwoo is HUGE. And it is because this Sangwoo has not the same qualities of the one he wanted, he doesn't like him anymore. Sangwoo crushed his ideals and reality hits very hard (Bum os sensitive enough to understand that) I don't think we have to think of Sangwoo as the love of his live. Bum was probably just unconsciously looking for someone with those characteristics (given all his dramatic situation), that he fell for Sangwoo. Sangwoo himslef is just fullfilling a role.

Thanks *blushes*.

I really wanted to believe that was the case until I read the latest chapters ( https://www.instagram.com/killingstalkingchapters6/ - thanks to Sacchan above for posting this xD) I can't believe that what he did there was just b/c he wanted to survive. He, just like he probably did there in the bathroom, acted out on a mixture of a lot of twisted and messed up emotions. On some lvl he still wants Sangwoo badly and at the same time he hates him and is scared for his life and.. Just thinking about his situation makes me feel so bad >.>

Aside from the concert I haven't see Bum demonstrating that he's trying to escape or still thinking about it. I understand pleasing Sangwoo until the perfect opportunity arises but I haven't seen Bum actively planning what to do to escape. Sangwoo has given him more freedom by taking him out in public but Bum has not used that to his advantage so it's no different than being locked in the house.
Love is a forgien concept to me too but I thought some people can fall in love due to some superficial qualities of a person and not actually know the person first. But anyways I didn't say Bum loved Sangwoo, I was referring to when Sangwoo embraced Bum and said "Let's stay together forever" in Chapter 13 and the "love confession" from Sangwoo in the car when he said "So you love me too." in chapter 15. I also believe Bum's initial attract was like an obsessive celebrity crush. However during the abuse Bum has struggled to let go of those feelings. He knows Sangwoo is manipulative and abusive but loves that idolized image of Sangwoo in his head. When Sangwoo embraced Bum in in chapter 13 and showed Bum affection those feelings resonated with Bum making it harder for him to let go of that glorified bimage. That's why in chapter 15 Bum thought "I can still feel your warmth embracing and holding onto me." And because Bum has not let go of these feelings I believe he is still sexually attracted to Sangwoo and has the same sexual fantasies he's had in the beginning (which was confirmed in the I wanted to suck you off moment) and is why I also believe he is jealous of Jieun's closeness to Sangwoo.
Note: I used quotes from the official on Lezhin. If the fan translations are posted for those chapters they might say something different.

There is a concept in psychology called learned helplessness where people who are continually slapped down stop trying. It was based on an experiment where (if I recall correctly), dogs were put in cages and the bottom of the cage periodically gave them painful electric shocks. Dogs in one group could stop the pain by pressing a bar. Dogs in the second group could not stop the pain not matter what they did. The dogs who figured out a way to stop it, confidently stopped it. The dogs who could not end the pain stopped trying. Even when the second group was put in the first group's cages and could have stopped the pain, they just lay there whimpering--because they had already learned it was pointless to try. *
I think that's kind of what happened to Bum. He tried to poison Sangwoo, and ended up being the one who got sick. He tried to escape and was nearly killed and had his chin cut. He tried to tell people, and not one believed him. And it didn't take Sangwoo long to follow Bum whenever he went to the bathroom. The only think that seems to kind of work is flattery and sucking cock--and this may be similar to patterns established with Bum's uncle (though I am speculating). Bum has learned to be "helpless" (except for flattery and sex).
There is a second phase that is also deadly for abuse victims--there are times Sangwoo makes Bum feel special. How would someone like Bum not treasure that no matter how messed up it is? I think Bum means it when he says he hates Sangwoo, but he feels confused and does like it when Sangwoo treats him nicely. How could someone like Bum not like the few times someone isn't kicking him in the teeth?
*PS I think the experimenters were sadists, but it proves the concept to people who don't believe in such conditioning or shaping of behavior. All people would have to do to convince me is present it as a"thought experiment" but there you go. At least no one cut into the dogs.
I don't understand why people think Bum is a puppet. His mistake was to get into Sangwoo's house, but from then on he played very well his cards. His is smart, and not in a bad way Sangwoon, hopefully for Bum, must be a narcissistic person and this is his weakness, otherwise he would almost be a perfect killer. In the firsts chapters he says that he killed the girl because "That bitch thought she's better than me" (Wtf. Are you serious?). Bum has come to understand his personality and knows that the only way he has to survive is to keep worshipping him. He tried to escape when they were at the event, but no one let him out. It's not like he could much more without causing a scandal and Sangwoo finding out. If Sangwoo find out that he tried to escape, he'll take revenge, and maybe even kill him. Bum is being cautious, which is good. And I don't really think he's jealous of the girl. He wants to be person closest to Sangwoo, but because he wants to survive. If Sangwoo really developes a cruch on that girl, he would want to get rid of Bum. And how do you get rid of someone who you've kept prisoner for months and knows all that you've done? By killing him, and we know this is not an issue for Sangwoo.