Are the nationalities of the crews involved known; I'd be surprised if at least were not Australian? Could they not still be subject to a sub-peona, notwithstanding the fact that they are working abroad?
Given the efforts EK (and the UAE govt) has put into getting extra access and rights into Oz, the airline would be very strongly advised to co-operate and to permit the crews involved to return. Given the seriousness of the incident, the Australian authorities could possibly impose sanctions, either temporarily and permanently.