That would be one of the worst things he could do.. Overeem would destroy him with GNP if they got to the ground.
Front kick Overeem's face 20 times until it knocks Overeem out
Stay away from the cage
If I were Mir's coach I would consider electrifying the cage that he trains in, to condition him into not touching it.
dont let overeem kick box and keep his distance, also dont let him clinch, the needs to be aggressive and take him down, but i dont see him being able to at this point in his career
don't get hit