In what circumstances will a defendant be convicted of kidnapping for purpose of robbery under section 654 of the California Criminal Code?

In People v. Nichols (1994) 29 Cal.App.4th 1651, 1654, the defendant and at least two others kidnapped a truck driver in order to steal pallets of compact discs, audiotapes, and videotapes from his trailer. As in the present case, defendant took the victim's driver's license and used his possession of the license to threaten the victim. The defendant told the victim, "If you open your mouth we are going to kill you. I know where you live." (Ibid.) The defendant argued section 654 precluded the court from sentencing him on the kidnapping for purpose of robbery and the threat under section 136.1. (Id. at p. 1656.)