Brock will need to open his gym to outsiders, this was the reason he wasn't prepared for an opponent like Cain. As a survival instinct we form habits that work. In the case of Brock Lesnar, it led to his downfall as the heavyweight champ. His gym "DEATH CLUTCH," located in a remote part of Minnesota, is not open to the public, and discourages any outside participation. Brock trains with a small group of select individuals, although these individuals are elite in their own styles, the amount of variables they present as sparring partners is limited.