An evidentiary hearing in Fulton County Superior Court got heated while District Attorney Fani Willis was on the stand being questioned by an attorney representing one of former President Donald Trump’s co-defendants. While attorney Ashleigh Merchant — who represents co-defendant Mike Roman — was trying to make the argument that Willis was unable to prove that there was no financial conflict of interest between herself and special prosecutor Nathan Wade, Willis suddenly interjected and sought to bring attention back to the original case. “You’re confused. You think I’m on trial. These people a…