Threats of opening fire on unarmed civilian vessels made on international distress frequencies are hardly 'mistakes' - they are cock-ups of the highest order.
One wonders what particular RoE were being 'simulated' at the time.
Foreign ships taking part in JMC are normally expected to be fully worked up - this does not sound like a 'mistake' to me, it sounds like incompetence almost of the Iranian Airbus level.....