"'A ruling on a motion to sequester witnesses rests within the sound discretion of the trial court, and the court's denial of the motion will not be disturbed in the absence of a showing that the was so arbitrary that it could not have been the result of a reasoned decision.' State v. Roache, 358 N.C. 243, 276-77, 595 S.E.2d 381, 404 (2004) (quoting State v. Hyde, 352 N.C. 37, 43, 530 S.E.2d 281, 286 (2000), cert. denied, 531 U.S. 1114, 148 L. Ed. 2d 775 (2001)).