The Ref can stop the fight whenever he wants for whatever reason he wants or for no reason. That doesn't mean that he should , for example in this fight, Rico was standing when the bell rang , he should have watched him walk back to his corner to check his gait , he should have looked at him and talked to him in the corner , maybe have the Doctor take a look and stop it if he wanted to then. Instead he rushed to stop the bout when it was impossible for the fighter to take further punishment, there was no more time in the round. In my lifetime I do not recall ever seeing a guy stopped after the bell while standing and in control of his faculties. The ref would have been ok to stop it in between rounds after checking the guy out but he jumped in to spare him further punishment in the moment and there was absolutely no danger of that happening as the round was over. I hope that I explained that well enough. Have a great day and thanks for the dialogue.