Of course it's Jaemin's doing!! Because who else would give the info to that desperate uggo..
As you said if Jaekyung beats him up, the match is affected and Dan will be blaming himself again. It has to be Dan who should shoulder throw that creeppo. I really hope he gets the courage to do that. (ᗒᗩᗕ)
I wish kim dan fights for real, jaekyung calls the police for trespassing and stalking they should take the safe route knowing jaekyung temper and kim dan experience it will be hard for him to control his anger + his tense about the upcoming match so yeah, i can't wait to jaemin get beatin in the ring for doing that

I'M PUTTING THIS ON SILENT AND LETTING IT MARINATE FOR 5 MONTHS OR MORE!!! THIS IS NOT GOOD FOR MY HEART (╥﹏╥)!!
Kim Dan please I beg of you BEAT THE SH*T OUT OF THAT F***ING OLD UGGO ( ノ`Д´)ノ彡┻━┻