Kathryn Dennis could not recall exactly when the three-car collision occurred that led up to her DUI arrest on Monday, according to the incident report obtained by RadarOnline.com which detailed how she wound up in custody. Dashcam footage from her run-in with the cops was released on Thursday, showing the former Southern Charm reality star completing field sobriety tests before she was cuffed and placed into a squad car. Dennis felt the arrest was unjust when the officer instructed the reality star to put her hands behind her back. “Wait why? Am I in trouble?” she asked. “Y’all are ruining my…