From E Online
"At the gala, Rachel was being flirtatious with Jay," a source exclusively tells E! News. "Once everyone was at the Boom Boom Room for the after-party, her flirtations were elevated."
"Beyoncé approached Rachel to let her know the behavior was disrespectful and she wanted her out of their lives for good," the source goes on. "Solange came over to have her sister's back, and things got heated with her and Rachel. Jay said some disrespectful things to Beyoncé and Solange as the confrontation was going down. That's why all hell broke loose in the elevator and why Beyoncé just stood back and let Solange hit Jay."