Train your mental skills in meditation. You learn to stay focused on a single thought and how to prevent or suppress random thoughts. This is slightly different advice and takes lots of work, but the skills you gain eliminate this problem in LDs 98%!

Short of that, I used to baffel them with funny BS
Say the agressive guy comes out towards you. You can address him with a made up story line, before one has developed. Like this" oh freak! You got the role, you look totally thrilled. Can you get me a back stage pass, please?!!!"

The DCs i have toyed with in this manner will become easy to handle.