Solange gives Jay Z a beating, while Beyoncé watches & does NOTHING...

TMZ has obtained some damning surveillance footage of Solange kicking, punching and screaming at Jay Z inside an elevator at a Met Gala after-party last week at the Standard Hotel in NYC. 

Jay Z is seen grabbing her foot after she tries to kick him. It's a good job the bodyguard was there to hold her back because at first Beyoncé just stood there and did NOTHING to protect her abused husband, lol. Bey was probably too scared to break a precious nail or probably agreed to some extent that Jay Z deserved to get his ass beat. She DID step forward... eventually. 

No one knows what triggered Solange's fiery wraith but to be a fly on the wall that night would have been an absolute blessing. The photo below was taken when the three emerged from the elevator. And clearly, Solange has a face like thunder.

It's creepy how Bey can just smile it up for the cameras SECONDS later:
While Jay Z's face looks butt hurt: