when you hit that stage when your confused or stressed that you no longer become yourself and have hit that mode when everything becomes crazy and you act all weird
Me: Yeah, I can't do this anymore, I've hit that mad mode
Mad mode is a state of mind when you're soul become berserker that boosted/overpower your strength, a person who turned the mad mode on is Mad man.
person "A" is physically bullying you and you are out of patience, in that moment.you're becoming Mad mode on so you're fight back and you're beating him more brutally than he did