Nowhere to run or clinch and no room to duck below the waistline? Would end badly for Floyd with anyone with power.
I can see Joe Cortez running up to the booth with tears streaming after the first punch lands on Floyd.
Seems like besides power, aggression & volume, unlike in much of boxing, shorter limbs are an advantage. Hard to get shots off & proper leverage if you are a Wilder, Fury, even Foreman compared to a Frazier, Tyson, even Ruiz. Chin would be very important too.
Depends on who is in the phone booth with him. He will survive against most but he will be beaten to a pulp if the opponent was Duran.