It really depends on how the rupture disc system was designed. The system you are using is a double bursting disc unit that provides double the protection for production equipment working under extreme conditions, such as highly corrosive environments or environmentally harmful or highly toxic substances. The response of the pressures of the two discs depends on the operating conditions and the burst pressures of the discs. If the burst pressure of the second disc (further from the vessel) was designed to be higher than the first disc, then it should remain intact. Also, you should have independent signaling units on each rupture disc so you would know if the second disc did rupture. Of course, if the first disc should rupture, to maintain the integrity of the system and its built-in safeguards, you should replace it immediately