Very interesting. This reminds me the situation from 1998 when one of B767 engines got on fire on take off from BKK and when the supervisor entered the flight deck for the info on situation she heard " get to **** out of here" - from the cpt. Sad but truth. Fortunatelly it was really experienced lady so the cabin crew knew what to do.
Other situation, an example of bad or even NO preflight briefing. On a WAW-JFK flight there was a bomb threat, that was disclosed short before landing. The crew were asked to prepare the cabin for prepared emergency landing. When the supervisor started to read the emergency PAs nobody knew where to stand in the cabin/the position to take during PAX briefing. Total mess.