Russia probably connived at Kim's recent nuclear test and they are responsible for that. (Notice their ambassador is calling it a 10kt explosion when everyone measured .5 kt? That's because he went by the spec they told him, and the rest went by the actual tremor, which showed a "squib").
But Chinese responsibility for North Korea goes beyond "encouraging". There are a million dead Chinese men buried on North Korea soil, who kept it North Korean after the United Nations freed it. China is morally responsible for every crime that resulted, for the past 2 generations.
This is your mess. Clean it up already.
I see your point in general, but I don't think that the guards had many realistic options in this case.