maybe Drew's getting sick of things in the house where others have stirred up trouble for him as well, or part of his gameplay to try get others to nominate each other...or he's just finds it amusing how others react to each other and situations in the house, where they wouldn't act or do those things in the outside world
ie Tim told Drew about overhearing Ed and Matt talking about bringing up the 'emotional cheating' subject at the family dinner, which later that night ended up with Drew in Tully's bad books.
Tim told Ed, that Ed had told Tully something which she then told Drew, and Drew told Tim and Tim told Ed..which caused the Ed and Tullys conflict that friday night about not putting her trust in Drew and Tim, which ended up wth Drew and Tully upset etc
Tim hinted to Tully in the bedroom that he overhead something when Drew and Jade were talking on the daybed, and Tully got mad and had go at Drew.