not knowing anything about the crash, but knowing plenty about the lie of the land up there, it is common for DOC workers to be picked up/dropped off by chopper from the emergency shelter (about 150-200' above the lake level), the only direction to go to climb away from rising ground, unless you have picked up on the top of the whakapapa glacier, is towards the lake. winds do funny things when they find a sudden blockage at 10000', and the rotoring coming over Turoa and over the summit ridge, could easily catch someone out. mauw (or near to), high altitude (it's easy to 'forget' you're at 10000' when the ground is 50 ft below you), unfavourable winds.....