For those who have not seen the news, a gunman with an AR-15 shot a Christchurch, New Zealand mosque Friday 3/15/2019 (one day ahead of the US) causing approximately 30 casualties. This was apparently motivated as revenge for Muslim atrocities and terrorist attacks.
Don't play dead. Get up and run away if you can. Expect them to circle back.
Having seen the footage, after shooting his victims in the mele, he shot them again in the head. He even left and came back to continue giving coup de grâce shots. There was plenty of time for a good guy with a gun to end the attack. These shootings are not as chaotic as one might think.
This is was a disturbingly competent shooter (compared to others). Plan and prepare for this guy. Not all spree killers will be as incompetent as we have seen.
Put your head on a swivel. It would not be unexpected for retaliatory terrorist attacks against Christians and Europeans to happen as a result.