Because I watched a guy do it on accident. He was screwing around with the new story mission with his buddy. One guy scanned praedyths bones while the other used the bones to get to the dorment portal gate at the far end of the jumping puzzle. Their buddy then joined them so they purposely wiped to spawn in the same place. And they ended up spawning inside the hidden area. Killed the vex juggernaut and opened praedyths door. With the new aquired ghost in hand they were summoned to the fwc lady for a quest.