Abstract: The presently disclosed technique pertains to in-line explosive trains, and, more particularly, to a dynamic switch for use in an in-line explosive train. In a first aspect, the presently disclosed technique includes a method for use in arming an in-line explosive train comprising: arming two S&A circuits independently of one another; transitioning each arming circuit to a dynamic control start state to initiate a pair of state machines, each state machine associate with a respective one of the S&A circuits; transitioning through the states of the state machine to turn a switch on and off. In a second aspect, the presently disclosed technique includes a dynamic safety switch for use in an in-line explosive train comprising: a pair of S&A circuits; a pair of state machines entering a predetermined cycle upon indication to arm from both the S&A circuits and cooperatively transitioning through the cycle; and a switch controlled by the cooperative transition of the state machines.