Once Lt. Singer finishes questioning her final witness, she states that she was resting her case. She wouldn't have rested until after all testimony from the witness was complete. By closing her case, she wouldn't be able to respond to any revelations that might come out of the testimony.
When Lt. Singer does an about-face to leave the Admiral's office after accepting the prosecutor role in Seaman McBride's court-martial she does the about-face to the left, which is incorrect, rather than doing the about-face to the right.