Clearly safety is the number one priority. A no-blame culture where this incident could be discussed properly with all the CC on that flight together will probably reveal that there were a littany of errors that led to this. Sacking the purser will not achieve anything as the errors and solutions have not been identified and the same will happen again.
On a different note the arm waving is a waste of time as far as I am concerned as it is done half heartedly and really does not indicate where the exits are.
FD.