There was no reaction. He didn’t even move.
With that in mind, Floyd Mayweather’s reaction to getting swung at by Mike Tyson is nothing short of incredible.
It happened quick enough that Floyd only had a fraction of a fraction of a second to subconsciously decide if Mike was playing around or if he should actually get out of the way. It’s not always how you react to something that means you have good reflexes, sometimes it’s also not reacting that matters. Tyson was trying to clown Floyd, but instead Mike clowned himself.