I would say that Lonnie saw Chris as the latter was preparing to train. Lonnie and Chris go back pretty far, so I'm sure Lonnie is used to playfully harassing Cormier as he does in the video.
Since Chris is also known for his use of rec drugs, I would say that he was on something in the video and that's why you see the pretty drastic mood swing right in the middle. In the beginning Chris is all for it and messing around, but then you can actually see his demeanor change midstream. That's when he got pissed off and walked out, acting like an ass. There were better ways for Chris to go about his exit, that's for sure.