I guess he saw the success Abril had but he shouldn't. Almost everyday he tried it Rios was able to make him pay and the final sequence of shots that led to the stoppage was bc he went to defend in that stance and completely got owned.
He didn't get hurt when he employed his shoulder roll. He got hurt when he tried to move back out to start working again. He dropped his hands and used both arms to push Rios back and Rios caught him during the push.