why did berto fail in his shoulder roll

[BetterCallSaul]

You can't learn advanced defensive techniques that late into you career. It's just asking for trouble. The shoulder roll also requires agility and quick reaction speeds to carry out successfully something that Berto's Hulk like frame isn't designed to do.

Floyd Mayweather has worked on that one manoeuvre his whole life and he still gets hit. What chance does Andre Berto have?