Almost every incident involving MMA fighters or boxing in street fights or against cops has them losing and losing badly. Sometimes with them literally getting permanent brain damage or getting killed. Jon Jones, the most psychotic MMA fighter outside of like War Machine, still ran after someone with a shotgun rather than go unarmed. Because even he knew that MMA champion level skills pale in comparison to just shooting someone. First lessons in military CQC/MCMAP are pretty much all about shooting someone at close range.
Street fights have no rules. Guns? Knives? Smashing someone's head against concrete? 2 on 1? 10 on 1? Sucker punches? You would be an idiot to engage in one. Hence why most of them involve copious amounts of drinking or gang violence being an initiator. Because not knowing if someone is armed or with a gang or if a bouncer might smash your head in from behind....but still choosing to fight anyways.....is about as stupid as you can get.