MGM is terrified because they see massive lawsuits coming - especially if they somehow failed to alert police promptly when the gunman fired 200 rounds into a hallway six minutes before he began shooting at the crowd. 

The story of the Vegas Sheriff's department has changed so often I don't believe or trust anything they say. Everything I read indicates an incompetent and inadequate response from a poorly trained and prepared department. The FBI should take over the investigation. "six minutes is not enough time to formulate a response?" Here is the response - you get as many cops on that floor as fast as possible and blow your way through the door shooting anyone you see holding a gun. 

It is becoming clear lives could have been saved. Now we are in the CYA and preparing for lawsuits stage.