Not sure why you would think such a thing.
If you are guilty the last thing you want to do is work with the person who's ONLY job is to find evidence to convict you of a crime. Conversely, if you are innocent, the last thing you want to do is work with the person who's ONLY job is to find evidence to convict you of a crime. Muller's job is the same either way and your best legal action remains the same as well.
One of the common misconceptions here is that Muller is actually supposed to get to the truth of the matter when that really is not what he is there to do. He is there to kind as much evidence as possible on any guilty parties within Trump's campaign. It is up to the judges, juries and in Trumps case the legislator to determine actual guilt or innocence.