What is the meaning of section 4530 of the California Criminal Code when it refers to the unlawful departure of a prisoner from the limits of his custody?

[5] Under well established principles of statutory interpretation, courts should give meaning to every statutory word if possible and should avoid a statutory construction that renders any word surplusage. ( Cooley v. Superior Court (2002) 29 Cal.4th 228, 249, 127 Cal.Rptr.2d 177, 57 P.3d 654.) Thus, the meaning of "the unlawful departure of a prisoner from the limits of his custody" must be understood in reference to the "state prison" from which the prisoner allegedly escaped in violation of section 4530. Thus, proof of escape from prison requires a showing that the prisoner has gone beyond the boundary of the prison facility having custody of that prisoner. An inmate who remains within the bounds of the prison has not escaped that prison even if he has broken out of his cell and breached interior security barriers.