How Would Boxing Referee Rule If Connor McGregor Would Roundhouse Elbow Floyd Mayweather Out of Clinch?

Imagine feared mixed-martial-arts fighter Connor McGregor in a boxing match against legendary boxer Floyd Mayweather, the two in a clinch at the center of the ring after exchanging punches, then out-of-trained-instinct McGregor spins to deliver a powerfully leveraged elbow cracking Mayweather in the face, so how would the referee rule, deduct a point or disqualification?