What started the drama...people can only speculate. Here's the fight, check it out:

Jay Z was attacked by Beyonce's sister Solange. She was kicking and swinging at him inside an elevator.

Look closely, you see the bodyguard hit the emergency stop switch on the 12th floor. Maybe to keep the fight private...

All three walked out of the building together. Queen Bey and Solange get in one car ... security walks Jay to a different one. Watch below: