I am sorry but no. With BDSM it has to come from both sides, Chanwoo actually got on two occasions to even stop the whole play but instead, he went along with it. BDSM is show & tell not guess and wing it. He didn't exploit his sub, instead he thought both were in the idea of having a threesome. MD tried to stop it by saying "is there something you wanna say or want me to do" Also; it is up to the sub to show and tell when it goes too far. Since BDSM is really not black & white. I am sorry but no.
Do you understand what coercion is? Did you miss completely MD's smirks? Did you miss the moment when Chanwoo was choked to death and didn't say no and the fact he is a victim of abuse?
MD was manipulative asshole. He put ultimatum on the guy who was just rejected and used. He was just betrayed and he is saying oooh if you won't participate in any I will abandon you too. Jesus people let's not play dumb.
MD tried to stop that? Yup definitely with the whole reminding... You can design any time you want... But it's the end of our relationship.
Before I start; sorry I should have made clear in my reaction that I do not agree with the ultimatum given by MD. it was putting Chan into this awful situation that shouldn't even happen in the first place. About the choking; I am more annoyed and hate to even say this but once you choke someone you need to have 100% their trust and seeing it displayed in such a way... is not oke....
That being said the thing with BDSM is, a question like; "should I do this" or even a simple "stop" is not your way out of the play, since with BDSM you use other words to indicate STOP etc. The stopwords depend on the agreement, but let's assume for now it isn't stop or a simple question. This is the MAIN reason you create PRIOR BDSM safety words/comfort zones (their safety word is vanilla, not sure if they have tapping as stop indicator once Chan is tied up). Oh well in the end, this play turned into a big mess & miscommunication on both ends but to put the blame only on MD (once again not talking his manipulation/choking good) that is not oke. Chan should have used the stop word. But MD is the bigger ass here for putting Chan in such a position, plus thinking he would be oke with that.
this is why in BDSM culture you use safewords since you cannot know or feel what the other feels! I think unlike most this pairing is lovely. Besides I think MD saw this as a little sexual game with two slaves, he wanted to see how far Chanwoo would go.... and well apparently his buffer is at seeing MD being kissed by another.