Trying to be as fair as possible.
In the middle of the night, Perez went over to the other side of the bedroom and coughed loudly (probably deliberately) near Alexander for some time. Alexander got angry and shouted at him. Most of the others were pissed off at Perez for it in the morning and he continued to feel isolated, Nadia tried to give him a pep-talk. At some point, Keith told Perez that he was finished with him and to leave him alone.
Later, Perez went over to the sitting area and stared at Alexander with a grin on his face. Some are saying it was provocative, others not. Alexander lost his rag, and used the F word, and Perez run off offended. BB gave Alexander a warning not to use language again. Katie confronted Perez and told him that if he was going to go around trying to pick fights, she'd be there to make his life miserable. She followed him into the bedroom in a tirade, he crawled into bed trying to ignore her. She also smashed some statue of a dog. (I didn't see how exactly that happened, I think she may have hit it out of anger?) Later, he went into the DR and demanded to see his lawyer, feeling unsafe around Alexander and Katie. At some point, Alicia got a bit upset, feeling like Perez is using her and the others dislike her in part because she's friendly with him.
Chloe was evicted and Katie came in. She chose Perez, Cami and Nadia to go in the jail thing. Perez heared the "get Perez out" chants and took it badly. (We saw all this on the eviction show!) Later Pricey told the others the story of how she found out her hubby was cheating.
I think that covers it. Obviously I have an opinion on the whole Perez thing, but I tried to be fairly neutral on what happened!