I am not ridiculing the aircrew, I don't think what they did is amusing or jokeworthy but, as you say, the SA was still in the readyroom and there is no real reason why it should have been
SA can be lost for innumerable reasons. Try this one that happened in our unit prior to my arrival.
Huey sitting on PSP in the revetment doing the cool down run. PIC dropped an item into the chin bubble, so hopped out leaving the co pilot to complete shut down. In attempting to retrieve dropped item he pushed a pedal full forward to gain access, with the result the tail boom slammed into the revetment wall. Experienced pilot at the end of a long day. Fatigue, dehydration, low blood sugar, awareness of CoF PSP and skids, in a rush to the loo? Who knows? RN QHI graduate.
As for the SA being in the ready room on the Wall St. incident, lets wait and see. There are many issues that can arise to detract from optimum personal performance, even in a seemingly simple evolution. Problems at home being just one.