That right hook was not a mistake. He deliberately gave up the outside space to draw the opponent inside, then caught him with the elbow. This was engineered.
Watch the southpaw-to-orthodox switch frame by frame: his weight transfer is deliberately 15-20 degrees wider than standard form โ baiting the opponent to misread the distance. The look on the opponent's face when the elbow landed was someone who didn't see it coming.
This level of setup requires precise distance management and timing. Not something a casual viewer catches on first watch. I watched seven times.